Mineral
In geology and mineralogy, a mineral or mineral species is, broadly speaking, a solid substance with a fairly well-defined chemical composition and a specific crystal structure that occurs naturally in pure form.[1][2]
The
The concept of mineral is distinct from rock, which is any bulk solid geologic material that is relatively homogeneous at a large enough scale. A rock may consist of one type of mineral or may be an aggregate of two or more different types of minerals, spacially segregated into distinct phases.[3]
Some natural solid substances without a definite crystalline structure, such as opal or obsidian, are more properly called mineraloids.[4] If a chemical compound occurs naturally with different crystal structures, each structure is considered a different mineral species. Thus, for example, quartz and stishovite are two different minerals consisting of the same compound, silicon dioxide.
The International Mineralogical Association (IMA) is the generally recognized standard body for the definition and nomenclature of mineral species. As of March 2024[update], the IMA recognizes 6031 official mineral species.[5]
The chemical composition of a named mineral species may vary somewhat due to the inclusion of small amounts of impurities. Specific
9S
8, meaning Fe
xNi
9-xS
8, where x is a variable number between 0 and 9. Sometimes a mineral with variable composition is split into separate species, more or less arbitrarily, forming a mineral group; that is the case of the silicates Ca
xMg
yFe
2-x-ySiO
4, the olivine group
Besides the essential chemical composition and crystal structure, the
Minerals are classified by key chemical constituents; the two dominant systems are the Dana classification and the Strunz classification. Silicate minerals comprise approximately 90% of the Earth's crust.[7][8] Other important mineral groups include the native elements, sulfides, oxides, halides, carbonates, sulfates, and phosphates.
Definitions
International Mineralogical Association
The International Mineralogical Association has established the following requirements for a substance to be considered a distinct mineral:[9][10]
- It must be a naturally occurring substance formed by natural geological processes, on Earth or other extraterrestrial bodies. This excludes compounds directly and exclusively generated by human activities ( Hypothetical substances are also excluded, even if they are predicted to occur in inaccessible natural environments like the Earth's core or other planets.
- It must be a solid substance in its natural occurrence. A major exception to this rule is native mercury: it is still classified as a mineral by the IMA, even though crystallizes only below −39 °C, because it was included before the current rules were established.[11] Water and carbon dioxide are not considered minerals, even though they are often found as inclusions in other minerals; but water ice is considered a mineral.[12]
- It must have a well-defined crystallographic structure; or, more generally, an ordered atomic arrangement.[13] This property implies several macroscopic physical properties, such as crystal form, hardness, and cleavage.[14] It excludes ozokerite, limonite, obsidian and many other amorphous (non-crystalline) materials that occur in geologic contexts.
- It must have a fairly well defined chemical composition. However, certain crystalline substances with a fixed structure but variable composition may be considered single mineral species. A common class of examples are solid solutions such as mackinawite, (Fe, Ni)9S8, which is mostly a ferrous sulfide with a significant fraction of iron atoms replaced by nickel atoms.[13][15] Other examples include layered crystals with variable layer stacking, or crystals that differ only in the regular arrangement of vacancies and substitutions. On the other hand, some substances that have a continuous series of compositions, may be arbitrarily split into several minerals. The typical example is the olivine group (Mg, Fe)2SiO4, whose magnesium-rich and iron-rich end-members are considered separate minerals (forsterite and fayalite).
The details of these rules are somewhat controversial.[13] For instance, there have been several recent proposals to classify amorphous substances as minerals, but they have not been accepted by the IMA.
The IMA is also reluctant to accept minerals that occur naturally only in the form of nanoparticles a few hundred atoms across, but has not defined a minimum crystal size.[9]
Some authors require the material to be a
As of March 2024[update], 6031 mineral species are approved by the IMA.[5] They are most commonly named after a person, followed by discovery location; names based on chemical composition or physical properties are the two other major groups of mineral name etymologies.[16][17] Most names end in "-ite"; the exceptions are usually names that were well-established before the organization of mineralogy as a discipline, for example galena and diamond.
Biogenic minerals
A topic of contention among geologists and mineralogists has been the IMA's decision to exclude biogenic crystalline substances. For example, Lowenstam (1981) stated that "organisms are capable of forming a diverse array of minerals, some of which cannot be formed inorganically in the biosphere."[18]
Skinner (2005) views all solids as potential minerals and includes biominerals in the mineral kingdom, which are those that are created by the metabolic activities of organisms. Skinner expanded the previous definition of a mineral to classify "element or compound, amorphous or crystalline, formed through biogeochemical processes," as a mineral.[19]
Recent advances in high-resolution genetics and X-ray absorption spectroscopy are providing revelations on the biogeochemical relations between microorganisms and minerals that may shed new light on this question.[10][19] For example, the IMA-commissioned "Working Group on Environmental Mineralogy and Geochemistry " deals with minerals in the hydrosphere, atmosphere, and biosphere.[20] The group's scope includes mineral-forming microorganisms, which exist on nearly every rock, soil, and particle surface spanning the globe to depths of at least 1600 metres below the sea floor and 70 kilometres into the stratosphere (possibly entering the mesosphere).[21][22][23]
Prior to the International Mineralogical Association's listing, over 60 biominerals had been discovered, named, and published.[27] These minerals (a sub-set tabulated in Lowenstam (1981)[18]) are considered minerals proper according to Skinner's (2005) definition.[19] These biominerals are not listed in the International Mineral Association official list of mineral names;[28] however, many of these biomineral representatives are distributed amongst the 78 mineral classes listed in the Dana classification scheme.[19]
Skinner's (2005) definition of a mineral takes this matter into account by stating that a mineral can be crystalline or amorphous.[19] Although biominerals are not the most common form of minerals,[29] they help to define the limits of what constitutes a mineral proper. Nickel's (1995) formal definition explicitly mentioned crystallinity as a key to defining a substance as a mineral. A 2011 article defined icosahedrite, an aluminium-iron-copper alloy, as a mineral; named for its unique natural icosahedral symmetry, it is a quasicrystal. Unlike a true crystal, quasicrystals are ordered but not periodic.[30][31]
Rocks, ores, and gems
A
In rocks, some mineral species and groups are much more abundant than others; these are termed the rock-forming minerals. The major examples of these are quartz, the feldspars, the micas, the amphiboles, the pyroxenes, the olivines, and calcite; except for the last one, all of these minerals are silicates.[37] Overall, around 150 minerals are considered particularly important, whether in terms of their abundance or aesthetic value in terms of collecting.[38]
Commercially valuable minerals and rocks, other than gemstones, metal ores, or mineral fuels, are referred to as
Ores are minerals that have a high concentration of a certain element, typically a metal. Examples are cinnabar (HgS), an ore of mercury; sphalerite (ZnS), an ore of zinc; cassiterite (SnO2), an ore of tin; and colemanite, an ore of boron.
Gems are minerals with an ornamental value, and are distinguished from non-gems by their beauty, durability, and usually, rarity. There are about 20 mineral species that qualify as gem minerals, which constitute about 35 of the most common gemstones. Gem minerals are often present in several varieties, and so one mineral can account for several different gemstones; for example, ruby and sapphire are both corundum, Al2O3.[41]
Etymology
The first known use of the word "mineral" in the
The word "species" comes from the Latin species, "a particular sort, kind, or type with distinct look, or appearance".[43]
Chemistry
The abundance and diversity of minerals is controlled directly by their chemistry, in turn dependent on elemental abundances in the Earth. The majority of minerals observed are derived from the Earth's crust. Eight elements account for most of the key components of minerals, due to their abundance in the crust. These eight elements, summing to over 98% of the crust by weight, are, in order of decreasing abundance: oxygen, silicon, aluminium, iron, magnesium, calcium, sodium and potassium. Oxygen and silicon are by far the two most important – oxygen composes 47% of the crust by weight, and silicon accounts for 28%.[44]
The minerals that form are those that are most stable at the temperature and pressure of formation, within the limits imposed by the bulk chemistry of the parent body.
The chemical composition may vary between
Chemical substitution and coordination polyhedra explain this common feature of minerals. In nature, minerals are not pure substances, and are contaminated by whatever other elements are present in the given chemical system. As a result, it is possible for one element to be substituted for another.[51] Chemical substitution will occur between ions of a similar size and charge; for example, K+ will not substitute for Si4+ because of chemical and structural incompatibilities caused by a big difference in size and charge. A common example of chemical substitution is that of Si4+ by Al3+, which are close in charge, size, and abundance in the crust. In the example of plagioclase, there are three cases of substitution. Feldspars are all framework silicates, which have a silicon-oxygen ratio of 2:1, and the space for other elements is given by the substitution of Si4+ by Al3+ to give a base unit of [AlSi3O8]−; without the substitution, the formula would be charge-balanced as SiO2, giving quartz.[52] The significance of this structural property will be explained further by coordination polyhedra. The second substitution occurs between Na+ and Ca2+; however, the difference in charge has to accounted for by making a second substitution of Si4+ by Al3+.[53]
Coordination polyhedra are geometric representations of how a cation is surrounded by an anion. In mineralogy, coordination polyhedra are usually considered in terms of oxygen, due its abundance in the crust. The base unit of silicate minerals is the silica tetrahedron – one Si4+ surrounded by four O2−. An alternate way of describing the coordination of the silicate is by a number: in the case of the silica tetrahedron, the silicon is said to have a coordination number of 4. Various cations have a specific range of possible coordination numbers; for silicon, it is almost always 4, except for very high-pressure minerals where the compound is compressed such that silicon is in six-fold (octahedral) coordination with oxygen. Bigger cations have a bigger coordination numbers because of the increase in relative size as compared to oxygen (the last
Because the eight most common elements make up over 98% of the Earth's crust, the small quantities of the other elements that are typically present are substituted into the common rock-forming minerals. The distinctive minerals of most elements are quite rare, being found only where these elements have been concentrated by geological processes, such as hydrothermal circulation, to the point where they can no longer be accommodated in common minerals.[55]
Changes in temperature and pressure and composition alter the mineralogy of a rock sample. Changes in composition can be caused by processes such as
- 2 KAlSi3O8 + 5 H2O + 2 H+ → Al2Si2O5(OH)4 + 4 H2SiO3 + 2 K+
Under low-grade metamorphic conditions, kaolinite reacts with quartz to form pyrophyllite (Al2Si4O10(OH)2):
- Al2Si2O5(OH)4 + SiO2 → Al2Si4O10(OH)2 + H2O
As metamorphic grade increases, the pyrophyllite reacts to form kyanite and quartz:
- Al2Si4O10(OH)2 → Al2SiO5 + 3 SiO2 + H2O
Alternatively, a mineral may change its crystal structure as a consequence of changes in temperature and pressure without reacting. For example, quartz will change into a variety of its SiO2
Physical properties
Classifying minerals ranges from simple to difficult. A mineral can be identified by several physical properties, some of them being sufficient for full identification without equivocation. In other cases, minerals can only be classified by more complex
Crystal structure and habit
Crystal structure results from the orderly geometric spatial arrangement of atoms in the internal structure of a mineral. This crystal structure is based on regular internal atomic or ionic arrangement that is often expressed in the geometric form that the crystal takes. Even when the mineral grains are too small to see or are irregularly shaped, the underlying crystal structure is always periodic and can be determined by X-ray diffraction.[13] Minerals are typically described by their symmetry content. Crystals are restricted to 32 point groups, which differ by their symmetry. These groups are classified in turn into more broad categories, the most encompassing of these being the six crystal families.[59]
These families can be described by the relative lengths of the three crystallographic axes, and the angles between them; these relationships correspond to the symmetry operations that define the narrower point groups. They are summarized below; a, b, and c represent the axes, and α, β, γ represent the angle opposite the respective crystallographic axis (e.g. α is the angle opposite the a-axis, viz. the angle between the b and c axes):[59]
Crystal family | Lengths | Angles | Common examples |
---|---|---|---|
Isometric | a = b = c | α = β = γ = 90° | Garnet, halite, pyrite |
Tetragonal
|
a = b ≠ c | α = β = γ = 90° | Rutile, zircon, andalusite |
Orthorhombic
|
a ≠ b ≠ c | α = β = γ = 90° | orthopyroxenes
|
Hexagonal
|
a = b ≠ c | α = β = 90°, γ = 120° | Quartz, calcite, tourmaline |
Monoclinic
|
a ≠ b ≠ c | α = γ = 90°, β ≠ 90° | Clinopyroxenes, orthoclase, gypsum
|
Triclinic
|
a ≠ b ≠ c | α ≠ β ≠ γ ≠ 90° | Anorthite, albite, kyanite |
The hexagonal crystal family is also split into two crystal systems – the
Chemistry and crystal structure together define a mineral. With a restriction to 32 point groups, minerals of different chemistry may have identical crystal structure. For example,
Polymorphism can extend beyond pure symmetry content. The aluminosilicates are a group of three minerals – kyanite, andalusite, and sillimanite – which share the chemical formula Al2SiO5. Kyanite is triclinic, while andalusite and sillimanite are both orthorhombic and belong to the dipyramidal point group. These differences arise corresponding to how aluminium is coordinated within the crystal structure. In all minerals, one aluminium ion is always in six-fold coordination with oxygen. Silicon, as a general rule, is in four-fold coordination in all minerals; an exception is a case like stishovite (SiO2, an ultra-high pressure quartz polymorph with rutile structure).[61] In kyanite, the second aluminium is in six-fold coordination; its chemical formula can be expressed as Al[6]Al[6]SiO5, to reflect its crystal structure. Andalusite has the second aluminium in five-fold coordination (Al[6]Al[5]SiO5) and sillimanite has it in four-fold coordination (Al[6]Al[4]SiO5).[62]
Differences in crystal structure and chemistry greatly influence other physical properties of the mineral. The carbon allotropes diamond and graphite have vastly different properties; diamond is the hardest natural substance, has an adamantine lustre, and belongs to the isometric crystal family, whereas graphite is very soft, has a greasy lustre, and crystallises in the hexagonal family. This difference is accounted for by differences in bonding. In diamond, the carbons are in sp3 hybrid orbitals, which means they form a framework where each carbon is covalently bonded to four neighbours in a tetrahedral fashion; on the other hand, graphite is composed of sheets of carbons in sp2 hybrid orbitals, where each carbon is bonded covalently to only three others. These sheets are held together by much weaker van der Waals forces, and this discrepancy translates to large macroscopic differences.[63]
Twinning is the intergrowth of two or more crystals of a single mineral species. The geometry of the twinning is controlled by the mineral's symmetry. As a result, there are several types of twins, including contact twins, reticulated twins, geniculated twins, penetration twins, cyclic twins, and polysynthetic twins. Contact, or simple twins, consist of two crystals joined at a plane; this type of twinning is common in spinel. Reticulated twins, common in rutile, are interlocking crystals resembling netting. Geniculated twins have a bend in the middle that is caused by start of the twin. Penetration twins consist of two single crystals that have grown into each other; examples of this twinning include cross-shaped staurolite twins and Carlsbad twinning in orthoclase. Cyclic twins are caused by repeated twinning around a rotation axis. This type of twinning occurs around three, four, five, six, or eight-fold axes, and the corresponding patterns are called threelings, fourlings, fivelings, sixlings, and eightlings. Sixlings are common in aragonite. Polysynthetic twins are similar to cyclic twins through the presence of repetitive twinning; however, instead of occurring around a rotational axis, polysynthetic twinning occurs along parallel planes, usually on a microscopic scale.[64][65]
Crystal habit refers to the overall shape of crystal. Several terms are used to describe this property. Common habits include acicular, which describes needlelike crystals as in natrolite, bladed, dendritic (tree-pattern, common in native copper), equant, which is typical of garnet, prismatic (elongated in one direction), and tabular, which differs from bladed habit in that the former is platy whereas the latter has a defined elongation. Related to crystal form, the quality of crystal faces is diagnostic of some minerals, especially with a petrographic microscope. Euhedral crystals have a defined external shape, while anhedral crystals do not; those intermediate forms are termed subhedral.[66][67]
Hardness
The hardness of a mineral defines how much it can resist scratching or indentation. This physical property is controlled by the chemical composition and crystalline structure of a mineral.
The most commonly used scale of measurement is the
Mohs hardness | Mineral | Chemical formula |
---|---|---|
1 | Talc | Mg3Si4O10(OH)2 |
2 | Gypsum | CaSO4·2H2O |
3 | Calcite | CaCO3 |
4 | Fluorite | CaF2 |
5 | Apatite | Ca5(PO4)3(OH,Cl,F) |
6 | Orthoclase | KAlSi3O8 |
7 | Quartz | SiO2 |
8 | Topaz | Al2SiO4(OH,F)2 |
9 | Corundum | Al2O3 |
10 | Diamond | C |
A mineral's hardness is a function of its structure. Hardness is not necessarily constant for all crystallographic directions; crystallographic weakness renders some directions softer than others.[68] An example of this hardness variability exists in kyanite, which has a Mohs hardness of 51⁄2 parallel to [001] but 7 parallel to [100].[69]
Other scales include these;[70]
- Shore's hardness test, which measures the endurance of a mineral based on the indentation of a spring-loaded contraption.[71]
- The Rockwell scale
- The Vickers hardness test
- The Brinell scale
Lustre and diaphaneity
Lustre indicates how light reflects from the mineral's surface, with regards to its quality and intensity. There are numerous qualitative terms used to describe this property, which are split into metallic and non-metallic categories. Metallic and sub-metallic minerals have high reflectivity like metal; examples of minerals with this lustre are galena and pyrite. Non-metallic lustres include: adamantine, such as in diamond; vitreous, which is a glassy lustre very common in silicate minerals; pearly, such as in talc and apophyllite; resinous, such as members of the garnet group; silky which is common in fibrous minerals such as asbestiform chrysotile.[72]
The
The diaphaneity of a mineral depends on the thickness of the sample. When a mineral is sufficiently thin (e.g., in a thin section for petrography), it may become transparent even if that property is not seen in a hand sample. In contrast, some minerals, such as hematite or pyrite, are opaque even in thin-section.[74]
Colour and streak
Colour is the most obvious property of a mineral, but it is often non-diagnostic.[75] It is caused by electromagnetic radiation interacting with electrons (except in the case of incandescence, which does not apply to minerals).[76] Two broad classes of elements (idiochromatic and allochromatic) are defined with regards to their contribution to a mineral's colour: Idiochromatic elements are essential to a mineral's composition; their contribution to a mineral's colour is diagnostic.[73][77] Examples of such minerals are malachite (green) and azurite (blue). In contrast, allochromatic elements in minerals are present in trace amounts as impurities. An example of such a mineral would be the ruby and sapphire varieties of the mineral corundum.[77] The colours of pseudochromatic minerals are the result of
In addition to simple body colour, minerals can have various other distinctive optical properties, such as play of colours,
The streak of a mineral refers to the colour of a mineral in powdered form, which may or may not be identical to its body colour.[77] The most common way of testing this property is done with a streak plate, which is made out of porcelain and coloured either white or black. The streak of a mineral is independent of trace elements[73] or any weathering surface.[77] A common example of this property is illustrated with hematite, which is coloured black, silver, or red in hand sample, but has a cherry-red[73] to reddish-brown streak.[77] Streak is more often distinctive for metallic minerals, in contrast to non-metallic minerals whose body colour is created by allochromatic elements.[73] Streak testing is constrained by the hardness of the mineral, as those harder than 7 powder the streak plate instead.[77]
Cleavage, parting, fracture, and tenacity
By definition, minerals have a characteristic atomic arrangement. Weakness in this crystalline structure causes planes of weakness, and the breakage of a mineral along such planes is termed cleavage. The quality of cleavage can be described based on how cleanly and easily the mineral breaks; common descriptors, in order of decreasing quality, are "perfect", "good", "distinct", and "poor". In particularly transparent minerals, or in thin-section, cleavage can be seen as a series of parallel lines marking the planar surfaces when viewed from the side. Cleavage is not a universal property among minerals; for example, quartz, consisting of extensively interconnected silica tetrahedra, does not have a crystallographic weakness which would allow it to cleave. In contrast, micas, which have perfect basal cleavage, consist of sheets of silica tetrahedra which are very weakly held together.[80][81]
As cleavage is a function of crystallography, there are a variety of cleavage types. Cleavage occurs typically in either one, two, three, four, or six directions. Basal cleavage in one direction is a distinctive property of the micas. Two-directional cleavage is described as prismatic, and occurs in minerals such as the amphiboles and pyroxenes. Minerals such as galena or halite have cubic (or isometric) cleavage in three directions, at 90°; when three directions of cleavage are present, but not at 90°, such as in calcite or rhodochrosite, it is termed rhombohedral cleavage. Octahedral cleavage (four directions) is present in fluorite and diamond, and sphalerite has six-directional dodecahedral cleavage.[80][81]
Minerals with many cleavages might not break equally well in all of the directions; for example, calcite has good cleavage in three directions, but gypsum has perfect cleavage in one direction, and poor cleavage in two other directions. Angles between cleavage planes vary between minerals. For example, as the amphiboles are double-chain silicates and the pyroxenes are single-chain silicates, the angle between their cleavage planes is different. The pyroxenes cleave in two directions at approximately 90°, whereas the amphiboles distinctively cleave in two directions separated by approximately 120° and 60°. The cleavage angles can be measured with a contact goniometer, which is similar to a protractor.[80][81]
Parting, sometimes called "false cleavage", is similar in appearance to cleavage but is instead produced by structural defects in the mineral, as opposed to systematic weakness. Parting varies from crystal to crystal of a mineral, whereas all crystals of a given mineral will cleave if the atomic structure allows for that property. In general, parting is caused by some stress applied to a crystal. The sources of the stresses include deformation (e.g. an increase in pressure), exsolution, or twinning. Minerals that often display parting include the pyroxenes, hematite, magnetite, and corundum.[80][82]
When a mineral is broken in a direction that does not correspond to a plane of cleavage, it is termed to have been fractured. There are several types of uneven fracture. The classic example is conchoidal fracture, like that of quartz; rounded surfaces are created, which are marked by smooth curved lines. This type of fracture occurs only in very homogeneous minerals. Other types of fracture are fibrous, splintery, and hackly. The latter describes a break along a rough, jagged surface; an example of this property is found in native copper.[83]
Tenacity is related to both cleavage and fracture. Whereas fracture and cleavage describes the surfaces that are created when a mineral is broken, tenacity describes how resistant a mineral is to such breaking. Minerals can be described as brittle, ductile, malleable, sectile, flexible, or elastic.[84]
Specific gravity
High specific gravity is a diagnostic property of a mineral. A variation in chemistry (and consequently, mineral class) correlates to a change in specific gravity. Among more common minerals, oxides and sulfides tend to have a higher specific gravity as they include elements with higher atomic mass. A generalization is that minerals with metallic or adamantine lustre tend to have higher specific gravities than those having a non-metallic to dull lustre. For example, hematite, Fe2O3, has a specific gravity of 5.26[87] while galena, PbS, has a specific gravity of 7.2–7.6,[88] which is a result of their high iron and lead content, respectively. A very high specific gravity is characteristic of native metals; for example, kamacite, an iron-nickel alloy common in iron meteorites has a specific gravity of 7.9,[89] and gold has an observed specific gravity between 15 and 19.3.[86][90]
Other properties
Other properties can be used to diagnose minerals. These are less general, and apply to specific minerals.
Dropping dilute
Minerals can also be tested for taste or smell. Halite, NaCl, is table salt; its potassium-bearing counterpart, sylvite, has a pronounced bitter taste. Sulfides have a characteristic smell, especially as samples are fractured, reacting, or powdered.[91]
Classification
Earliest classifications
In 315
Georgius Agricola's classification of minerals in his book De Natura Fossilium, published in 1546, divided minerals into three types of substance: simple (stones, earths, metals, and congealed juices), compound (intimately mixed) and composite (separable).[94]
Linnaeus
An early classification of minerals was given by
Modern classification
Minerals are classified by variety, species, series and group, in order of increasing generality. The basic level of definition is that of mineral species, each of which is distinguished from the others by unique chemical and physical properties. For example, quartz is defined by its
Two common classifications, Dana and Strunz, are used for minerals; both rely on composition, specifically with regards to important chemical groups, and structure.
As the composition of the Earth's crust is dominated by silicon and oxygen, silicates are by far the most important class of minerals in terms of rock formation and diversity. However, non-silicate minerals are of great economic importance, especially as ores.[97][98] Non-silicate minerals are subdivided into several other classes by their dominant chemistry, which includes native elements, sulfides, halides, oxides and hydroxides, carbonates and nitrates, borates, sulfates, phosphates, and organic compounds. Most non-silicate mineral species are rare (constituting in total 8% of the Earth's crust), although some are relatively common, such as calcite, pyrite, magnetite, and hematite. There are two major structural styles observed in non-silicates: close-packing and silicate-like linked tetrahedra. Close-packed structures are a way to densely pack atoms while minimizing interstitial space. Hexagonal close-packing involves stacking layers where every other layer is the same ("ababab"), whereas cubic close-packing involves stacking groups of three layers ("abcabcabc"). Analogues to linked silica tetrahedra include SO4−
4 (sulfate), PO4−
4 (phosphate), AsO4−
4 (arsenate), and VO4−
4 (vanadate) structures. The non-silicates have great economic importance, as they concentrate elements more than the silicate minerals do.[99]
The largest grouping of minerals by far are the
Silicates
The base unit of a silicate mineral is the [SiO4]4− tetrahedron. In the vast majority of cases, silicon is in four-fold or tetrahedral coordination with oxygen. In very high-pressure situations, silicon will be in six-fold or octahedral coordination, such as in the
The degree of polymerization can be described by both the structure formed and how many tetrahedral corners (or coordinating oxygens) are shared (for aluminium and silicon in tetrahedral sites):[103][104]
- Orthosilicates (or nesosilicates)
- Have no linking of polyhedra, thus tetrahedra share no corners.
- Disilicates (or sorosilicates)
- Have two tetrahedra sharing one oxygen atom.
- Inosilicates are chain silicates
- Single-chain silicates have two shared corners, whereas double-chain silicates have two or three shared corners.
- Phyllosilicates
- Have a sheet structure which requires three shared oxygens; in the case of double-chain silicates, some tetrahedra must share two corners instead of three as otherwise a sheet structure would result.
- Framework silicates (or tectosilicates)
- Have tetrahedra that share all four corners.
- Ring silicates (or cyclosilicates)
- Only need tetrahedra to share two corners to form the cyclical structure.[104]
The silicate subclasses are described below in order of decreasing polymerization.
Tectosilicates
Tectosilicates, also known as framework silicates, have the highest degree of polymerization. With all corners of a tetrahedra shared, the silicon:oxygen ratio becomes 1:2. Examples are quartz, the feldspars, feldspathoids, and the zeolites. Framework silicates tend to be particularly chemically stable as a result of strong covalent bonds.[105]
Forming 12% of the Earth's crust, quartz (SiO2) is the most abundant mineral species. It is characterized by its high chemical and physical resistivity. Quartz has several polymorphs, including tridymite and cristobalite at high temperatures, high-pressure coesite, and ultra-high pressure stishovite. The latter mineral can only be formed on Earth by meteorite impacts, and its structure has been compressed so much that it has changed from a silicate structure to that of rutile (TiO2). The silica polymorph that is most stable at the Earth's surface is α-quartz. Its counterpart, β-quartz, is present only at high temperatures and pressures (changes to α-quartz below 573 °C at 1 bar). These two polymorphs differ by a "kinking" of bonds; this change in structure gives β-quartz greater symmetry than α-quartz, and they are thus also called high quartz (β) and low quartz (α).[100][106]
Feldspars are the most abundant group in the Earth's crust, at about 50%. In the feldspars, Al3+ substitutes for Si4+, which creates a charge imbalance that must be accounted for by the addition of cations. The base structure becomes either [AlSi3O8]− or [Al2Si2O8]2− There are 22 mineral species of feldspars, subdivided into two major subgroups – alkali and plagioclase – and two less common groups – celsian and banalsite. The alkali feldspars are most commonly in a series between potassium-rich orthoclase and sodium-rich albite; in the case of plagioclase, the most common series ranges from albite to calcium-rich anorthite. Crystal twinning is common in feldspars, especially polysynthetic twins in plagioclase and Carlsbad twins in alkali feldspars. If the latter subgroup cools slowly from a melt, it forms exsolution lamellae because the two components – orthoclase and albite – are unstable in solid solution. Exsolution can be on a scale from microscopic to readily observable in hand-sample; perthitic texture forms when Na-rich feldspar exsolve in a K-rich host. The opposite texture (antiperthitic), where K-rich feldspar exsolves in a Na-rich host, is very rare.[107]
Feldspathoids are structurally similar to feldspar, but differ in that they form in Si-deficient conditions, which allows for further substitution by Al3+. As a result, feldspathoids are almost never found in association with quartz. A common example of a feldspathoid is nepheline ((Na, K)AlSiO4); compared to alkali feldspar, nepheline has an Al2O3:SiO2 ratio of 1:2, as opposed to 1:6 in alkali feldspar.[108] Zeolites often have distinctive crystal habits, occurring in needles, plates, or blocky masses. They form in the presence of water at low temperatures and pressures, and have channels and voids in their structure. Zeolites have several industrial applications, especially in waste water treatment.[109]
Phyllosilicates
Phyllosilicates consist of sheets of polymerized tetrahedra. They are bound at three oxygen sites, which gives a characteristic silicon:oxygen ratio of 2:5. Important examples include the
The kaolinite-serpentine group consists of T-O stacks (the 1:1 clay minerals); their hardness ranges from 2 to 4, as the sheets are held by hydrogen bonds. The 2:1 clay minerals (pyrophyllite-talc) consist of T-O-T stacks, but they are softer (hardness from 1 to 2), as they are instead held together by van der Waals forces. These two groups of minerals are subgrouped by octahedral occupation; specifically, kaolinite and pyrophyllite are dioctahedral whereas serpentine and talc trioctahedral.[112]
Micas are also T-O-T-stacked phyllosilicates, but differ from the other T-O-T and T-O-stacked subclass members in that they incorporate aluminium into the tetrahedral sheets (clay minerals have Al3+ in octahedral sites). Common examples of micas are muscovite, and the biotite series. Mica T-O-T layers are bonded together by metal ions, giving them a greater hardness than other phyllosilicate minerals, though they retain perfect basal cleavage.[113] The chlorite group is related to mica group, but a brucite-like (Mg(OH)2) layer between the T-O-T stacks.[114]
Because of their chemical structure, phyllosilicates typically have flexible, elastic, transparent layers that are electrical insulators and can be split into very thin flakes. Micas can be used in electronics as insulators, in construction, as optical filler, or even cosmetics. Chrysotile, a species of serpentine, is the most common mineral species in industrial asbestos, as it is less dangerous in terms of health than the amphibole asbestos.[115]
Inosilicates
Inosilicates consist of tetrahedra repeatedly bonded in chains. These chains can be single, where a tetrahedron is bound to two others to form a continuous chain; alternatively, two chains can be merged to create double-chain silicates. Single-chain silicates have a silicon:oxygen ratio of 1:3 (e.g. [Si2O6]4−), whereas the double-chain variety has a ratio of 4:11, e.g. [Si8O22]12−. Inosilicates contain two important rock-forming mineral groups; single-chain silicates are most commonly pyroxenes, while double-chain silicates are often amphiboles.[116] Higher-order chains exist (e.g. three-member, four-member, five-member chains, etc.) but they are rare.[117]
The pyroxene group consists of 21 mineral species.[118] Pyroxenes have a general structure formula of XY(Si2O6), where X is an octahedral site, while Y can vary in coordination number from six to eight. Most varieties of pyroxene consist of permutations of Ca2+, Fe2+ and Mg2+ to balance the negative charge on the backbone. Pyroxenes are common in the Earth's crust (about 10%) and are a key constituent of mafic igneous rocks.[119]
Amphiboles have great variability in chemistry, described variously as a "mineralogical garbage can" or a "mineralogical shark swimming a sea of elements". The backbone of the amphiboles is the [Si8O22]12−; it is balanced by cations in three possible positions, although the third position is not always used, and one element can occupy both remaining ones. Finally, the amphiboles are usually hydrated, that is, they have a hydroxyl group ([OH]−), although it can be replaced by a fluoride, a chloride, or an oxide ion.[120] Because of the variable chemistry, there are over 80 species of amphibole, although variations, as in the pyroxenes, most commonly involve mixtures of Ca2+, Fe2+ and Mg2+.[118] Several amphibole mineral species can have an asbestiform crystal habit. These asbestos minerals form long, thin, flexible, and strong fibres, which are electrical insulators, chemically inert and heat-resistant; as such, they have several applications, especially in construction materials. However, asbestos are known carcinogens, and cause various other illnesses, such as asbestosis; amphibole asbestos (anthophyllite, tremolite, actinolite, grunerite, and riebeckite) are considered more dangerous than chrysotile serpentine asbestos.[121]
Cyclosilicates
Cyclosilicates, or ring silicates, have a ratio of silicon to oxygen of 1:3. Six-member rings are most common, with a base structure of [Si6O18]12−; examples include the tourmaline group and beryl. Other ring structures exist, with 3, 4, 8, 9, 12 having been described.[122] Cyclosilicates tend to be strong, with elongated, striated crystals.[123]
Tourmalines have a very complex chemistry that can be described by a general formula XY3Z6(BO3)3T6O18V3W. The T6O18 is the basic ring structure, where T is usually Si4+, but substitutable by Al3+ or B3+. Tourmalines can be subgrouped by the occupancy of the X site, and from there further subdivided by the chemistry of the W site. The Y and Z sites can accommodate a variety of cations, especially various transition metals; this variability in structural transition metal content gives the tourmaline group greater variability in colour. Other cyclosilicates include beryl, Al2Be3Si6O18, whose varieties include the gemstones emerald (green) and aquamarine (bluish). Cordierite is structurally similar to beryl, and is a common metamorphic mineral.[124]
Sorosilicates
Sorosilicates, also termed disilicates, have tetrahedron-tetrahedron bonding at one oxygen, which results in a 2:7 ratio of silicon to oxygen. The resultant common structural element is the [Si2O7]6− group. The most common disilicates by far are members of the epidote group. Epidotes are found in variety of geologic settings, ranging from mid-ocean ridge to granites to metapelites. Epidotes are built around the structure [(SiO4)(Si2O7)]10− structure; for example, the mineral species epidote has calcium, aluminium, and ferric iron to charge balance: Ca2Al2(Fe3+, Al)(SiO4)(Si2O7)O(OH). The presence of iron as Fe3+ and Fe2+ helps buffer oxygen fugacity, which in turn is a significant factor in petrogenesis.[125]
Other examples of sorosilicates include lawsonite, a metamorphic mineral forming in the blueschist facies (subduction zone setting with low temperature and high pressure), vesuvianite, which takes up a significant amount of calcium in its chemical structure.[125][126]
Orthosilicates
Orthosilicates consist of isolated tetrahedra that are charge-balanced by other cations.[127] Also termed nesosilicates, this type of silicate has a silicon:oxygen ratio of 1:4 (e.g. SiO4). Typical orthosilicates tend to form blocky equant crystals, and are fairly hard.[128] Several rock-forming minerals are part of this subclass, such as the aluminosilicates, the olivine group, and the garnet group.
The aluminosilicates –bkyanite, andalusite, and sillimanite, all Al2SiO5 – are structurally composed of one [SiO4]4− tetrahedron, and one Al3+ in octahedral coordination. The remaining Al3+ can be in six-fold coordination (kyanite), five-fold (andalusite) or four-fold (sillimanite); which mineral forms in a given environment is depend on pressure and temperature conditions. In the olivine structure, the main olivine series of (Mg, Fe)2SiO4 consist of magnesium-rich forsterite and iron-rich fayalite. Both iron and magnesium are in octahedral by oxygen. Other mineral species having this structure exist, such as tephroite, Mn2SiO4.[129] The garnet group has a general formula of X3Y2(SiO4)3, where X is a large eight-fold coordinated cation, and Y is a smaller six-fold coordinated cation. There are six ideal endmembers of garnet, split into two group. The pyralspite garnets have Al3+ in the Y position: pyrope (Mg3Al2(SiO4)3), almandine (Fe3Al2(SiO4)3), and spessartine (Mn3Al2(SiO4)3). The ugrandite garnets have Ca2+ in the X position: uvarovite (Ca3Cr2(SiO4)3), grossular (Ca3Al2(SiO4)3) and andradite (Ca3Fe2(SiO4)3). While there are two subgroups of garnet, solid solutions exist between all six end-members.[127]
Other orthosilicates include zircon, staurolite, and topaz. Zircon (ZrSiO4) is useful in geochronology as U6+ can substitute for Zr4+; furthermore, because of its very resistant structure, it is difficult to reset it as a chronometer. Staurolite is a common metamorphic intermediate-grade index mineral. It has a particularly complicated crystal structure that was only fully described in 1986. Topaz (Al2SiO4(F, OH)2, often found in granitic pegmatites associated with tourmaline, is a common gemstone mineral.[130]
Non-silicates
Native elements
The gold group, with a cubic close-packed structure, includes metals such as gold, silver, and copper. The platinum group is similar in structure to the gold group. The iron-nickel group is characterized by several iron-nickel alloy species. Two examples are kamacite and taenite, which are found in iron meteorites; these species differ by the amount of Ni in the alloy; kamacite has less than 5–7% nickel and is a variety of native iron, whereas the nickel content of taenite ranges from 7–37%. Arsenic group minerals consist of semi-metals, which have only some metallic traits; for example, they lack the malleability of metals. Native carbon occurs in two allotropes, graphite and diamond; the latter forms at very high pressure in the mantle, which gives it a much stronger structure than graphite.[131]
Sulfides
The
Oxides
Halides
The
Carbonates
The
Sulfates
The
Phosphates
The
Organic minerals
The Strunz classification includes a class for
Recent advances
Mineral classification schemes and their definitions are evolving to match recent advances in mineral science. Recent changes have included the addition of an organic class, in both the new Dana and the
Astrobiology
It has been suggested that
In January 2014, NASA reported that studies by the
See also
- Agrominerals
- Amateur geology – Non-professional study and collecting of rocks
- Isomorphism (crystallography) – Similarity of symmetry and shape
- List of minerals – List of minerals with Wikipedia articles
- List of minerals recognized by the International Mineralogical Association
- Mineral collecting – Hobby of systematically collecting, identifying and displaying mineral specimens
- Mineral evolution – Increasing mineral diversity over time
- Mineral (nutrient), also known as dietary mineral – Chemical element required as an essential nutrient by organisms to perform life functions
- Polymorphism (materials science)– Ability of a solid material to exist in more than one form or crystal structure
References
- ISBN 978-1-61530-489-9
- ISBN 978-0-521-52958-7.
- ^ Stephenson, Tim; Stephenson, Carolyn. "Rocks & Minerals". Creetown Gem Rock Museum. Archived from the original on 18 July 2019. Retrieved 18 July 2019.
- .
- ^ a b "The official IMA-CNMNC List of Mineral Names". IMA Commission on New Minerals, Nomenclature and Classification. Archived from the original on 20 July 2023. Retrieved 28 March 2024.
- ^ "Definition of mineral variety". mindat.org. Archived from the original on 2 March 2018. Retrieved 1 March 2018.
- ISBN 0-471-57452-X.
- ^ Klein, Cornelis (14 October 2019). "Mineral – Silicates". Encyclopedia Britannica. Archived from the original on 25 October 2017. Retrieved 20 April 2021.
- ^
- ^ a b c Nickel, Ernest H. (1995). "The definition of a mineral". The Canadian Mineralogist. 33 (3): 689–90. Archived from the original on 2018-08-25. Retrieved 2018-04-04.
- ^ "Mercury". Mindat.org. Archived from the original on 7 January 2018. Retrieved 3 April 2018.
- ^ "Ice". Mindat.org. Archived from the original on 4 June 2020. Retrieved 3 April 2018.
- ^ ISBN 978-0-939950-81-2.
- ^ Chesterman & Lowe 2008, pp. 13–14
- ^ "Mackinawite". Mindat.org. Archived from the original on 3 January 2019. Retrieved 3 April 2018.
- ^ a b Dyar & Gunter 2008, pp. 20–22
- ^ Dyar & Gunter 2008, p. 556
- ^ PMID 7008198.
- ^ S2CID 232388764.
- ^ "Working Group on Environmental Mineralogy and Geochemistry". Commissions, working groups and committees. International Mineralogical Association. 3 August 2011. Archived from the original on 8 March 2020. Retrieved 4 April 2018.
- ISBN 978-1-139-49459-5.
- from the original on 2020-05-10. Retrieved 2019-02-01.
- PMID 19527292.
- S2CID 1235688.
- S2CID 19993145.
- S2CID 130343033.
- PMID 17800080.
- ^ Official IMA list of mineral names (updated from March 2009 list) Archived 2011-07-06 at the Wayback Machine. uws.edu.au
- ISBN 978-1-4443-3460-9.
- S2CID 101152220.
- ^ Commission on New Minerals and Mineral Names, Approved as new mineral Archived 2012-03-20 at the Wayback Machine
- ^ a b Chesterman & Lowe 2008, pp. 15–16
- ^ Chesterman & Lowe 2008, pp. 719–21
- ^ Chesterman & Lowe 2008, pp. 747–48
- ^ Chesterman & Lowe 2008, pp. 694–96
- ^ Chesterman & Lowe 2008, pp. 728–30
- ^ Dyar & Gunter 2008, p. 15
- ^ Chesterman & Lowe 2008, p. 14
- ISBN 0-922152-34-9.
- ^ Nesse 2000, p. 246.
- ^ Chesterman & Lowe 2008, pp. 14–15
- ^ "mineral Archived 2020-10-02 at the Wayback Machine" entry in the Merriam-Webster online dictionary. Accessed on 2020-08-28.
- ^ Harper, Douglas. "Online Etymology Dictionary". etymonline. Archived from the original on 29 March 2018. Retrieved 28 March 2018.
- ^ a b Dyar & Gunter 2008, pp. 4–7
- ISBN 0-442-27624-9.
- ISBN 0-7167-2438-3.
- ^ Nesse 2000, p. 226.
- ISBN 978-0-521-88006-0.
- ^ Dyar & Gunter 2008, p. 586
- ^ Nesse 2000, pp. 308, 352.
- ^ Dyar & Gunter 2008, p. 141
- ^ Dyar & Gunter 2008, p. 14
- ^ Dyar & Gunter 2008, p. 585
- ^ Dyar & Gunter 2008, pp. 12–17
- ^ Sinkankas 1964, pp. 238–239.
- ^ Dyar & Gunter 2008, p. 549
- ^ Dyar & Gunter 2008, p. 579
- ^ Dyar & Gunter 2008, pp. 22–23
- ^ a b Dyar & Gunter 2008, pp. 69–80
- ^ Dyar & Gunter 2008, pp. 654–55
- ^ Dyar & Gunter 2008, p. 581
- ^ Dyar & Gunter 2008, pp. 631–32
- ^ Dyar & Gunter 2008, p. 166
- ^ Dyar & Gunter 2008, pp. 41–43
- ^ Chesterman & Lowe 2008, p. 39
- ^ Dyar & Gunter 2008, pp. 32–39
- ^ Chesterman & Lowe 2008, p. 38
- ^ a b Dyar & Gunter 2008, pp. 28–29
- ^ "Kyanite". Mindat.org. Archived from the original on 14 September 2019. Retrieved 3 April 2018.
- ^ "Hardness: Vickers, Rockwell, Brinell, Mohs, Shore and Knoop - Matmatch". matmatch.com. Archived from the original on 4 October 2021. Retrieved 4 October 2021.
- ^ "Hardness". 7 July 2007. Archived from the original on 2007-07-07. Retrieved 4 October 2021.
- ^ Dyar and Darby, pp. 26–28
- ^ a b c d e Busbey et al. 2007, p. 72
- ^ a b Dyar & Gunter 2008, p. 25
- ^ Dyar & Gunter 2008, p. 23
- ^ Dyar & Gunter 2008, pp. 131–44
- ^ a b c d e f Dyar & Gunter 2008, p. 24
- ^ a b Dyar & Gunter 2008, pp. 24–26
- ^ a b Busbey et al. 2007, p. 73
- ^ a b c d Dyar & Gunter 2008, pp. 39–40
- ^ a b c Chesterman & Lowe 2008, pp. 29–30
- ^ Chesterman & Lowe 2008, pp. 30–31
- ^ Dyar & Gunter 2008, pp. 31–33
- ^ Dyar & Gunter 2008, pp. 30–31
- ^ Nesse 2000, p. 97.
- ^ a b Dyar & Gunter 2008, pp. 43–44
- ^ "Hematite". Mindat.org. Archived from the original on 11 May 2020. Retrieved 3 April 2018.
- ^ "Galena". Mindat.org. Archived from the original on 11 May 2020. Retrieved 3 April 2018.
- ^ "Kamacite". Webmineral.com. Archived from the original on 13 December 2017. Retrieved 3 April 2018.
- ^ "Gold". Mindat.org. Archived from the original on 27 April 2018. Retrieved 3 April 2018.
- ^ a b c d Dyar & Gunter 2008, pp. 44–45
- ^ "Mineral Identification Key: Radioactivity, Magnetism, Acid Reactions". Mineralogical Society of America. Archived from the original on 2012-09-22. Retrieved 2012-08-15.
- .
- ^ ISBN 978-0-87933-184-9. Archivedfrom the original on 2018-06-02. Retrieved 2020-08-29.
- ISBN 978-3-642-64783-3. Archivedfrom the original on 2018-11-14. Retrieved 2018-11-13.
- ^ Dyar & Gunter 2008, pp 558–59
- ^ Dyar & Gunter 2008, p. 641
- ^ a b Dyar & Gunter 2008, p. 681
- ^ Dyar & Gunter 2008, pp. 641–43
- ^ a b Dyar & Gunter 2008, p. 104
- ^ Dyar & Gunter 2008, p. 5
- ^ Dyar & Gunter 2008, pp. 104–20
- ^ Dyar & Gunter 2008, p. 105
- ^ a b Dyar & Gunter 2008, pp. 104–17
- ^ Klein & Hurlbut 1993, p. 524.
- ^ Dyar & Gunter 2008, pp. 578–83
- ^ Dyar & Gunter 2008, pp. 583–88
- ^ Dyar & Gunter 2008, p. 588
- ^ Dyar & Gunter 2008, pp. 589–93
- ^ Dyar & Gunter 2008, p. 110
- ^ Chesterman & Lowe 2008, p. 525
- ^ Dyar & Gunter 2008, pp. 110–13
- ^ Nesse 2000, p. 238.
- ^ Dyar & Gunter 2008, pp. 602–05
- ^ Dyar & Gunter 2008, pp. 593–95
- ^ Chesterman & Lowe 2008, p. 537
- ^ "09.D Inosilicates". Webmineral.com. Archived from the original on 2017-07-02. Retrieved 2012-08-20.
- ^ a b Dyar & Gunter 2008, p. 112
- ^ Dyar & Gunter 2008 pp. 612–13
- ^ Dyar & Gunter 2008, pp. 606–12
- ^ Dyar & Gunter 2008, pp. 611–12
- ^ Dyar & Gunter 2008, pp. 113–15
- ^ Chesterman & Lowe 2008, p. 558
- ^ Dyar & Gunter 2008, pp. 617–21
- ^ a b Dyar & Gunter 2008, pp. 612–27
- ^ Chesterman & Lowe 2008, pp. 565–73
- ^ a b Dyar & Gunter 2008, pp. 116–17
- ^ Chesterman & Lowe 2008, p. 573
- ^ Chesterman & Lowe 2008, pp. 574–75
- ^ Dyar & Gunter 2008, pp. 627–34
- ^ Dyar & Gunter 2008, pp. 644–48
- ^ Chesterman & Lowe 2008, p. 357
- ^ Dyar & Gunter 2008, p. 649
- ^ Dyar & Gunter 2008, pp. 651–54
- ^ Dyar & Gunter 2008, p. 654
- ^ Chesterman & Lowe 2008, p. 383
- ^ Chesterman & Lowe 2008, pp. 400–03
- ^ Dyar & Gunter 2008, pp. 657–60
- ^ Dyar & Gunter 2008, pp. 663–64
- ^ Dyar & Gunter 2008, pp. 660–63
- ^ Chesterman & Lowe 2008, pp. 425–30
- ^ Chesterman & Lowe 2008, p. 431
- ^ Dyar & Gunter 2008, p. 667
- ^ Dyar & Gunter 2008, pp. 668–69
- ^ Chesterman & Lowe 2008, p. 453
- ^ Chesterman & Lowe 2008, pp. 456–57
- ^ Dyar & Gunter 2008, p. 674
- ^ Dyar & Gunter 2008, pp. 672–73
- ^ Dyar & Gunter 2008, pp. 675–80
- ^ "Dana Classification 8th edition – Organic Compounds". mindat.org. Archived from the original on 12 November 2016. Retrieved 3 April 2018.
- ^ "Nickel-Strunz Classification – silicates (Germanates) 10th edition". mindat.org. Archived from the original on 5 November 2018. Retrieved 3 April 2018.
- ^ hdl:2268/29163.
- ^ IMA divisions Archived 2011-08-10 at the Wayback Machine. Ima-mineralogy.org (2011-01-12). Retrieved on 2011-10-20.
- Mars Exploration Program Analysis Group (MEPAG) – NASA. p. 72. Archivedfrom the original on 2020-05-11. Retrieved 2009-07-22.
- ^ PMID 24458635.
- ^ a b "Exploring Martian Habitability". Science. 343 (6169): 345–452. January 24, 2014.
- ^ "Special Collection – Curiosity – Exploring Martian Habitability". Science. January 24, 2014. Archived from the original on April 20, 2020. Retrieved January 24, 2014.
- S2CID 52836398.
General references
- Busbey, A.B.; Coenraads, R.E.; Roots, D.; Willis, P. (2007). Rocks and Fossils. San Francisco: Fog City Press. ISBN 978-1-74089-632-0.
- Chesterman, C.W.; Lowe, K.E. (2008). Field guide to North American rocks and minerals. Toronto: Random House of Canada. ISBN 978-0-394-50269-4.
- Dyar, M.D.; Gunter, M.E. (2008). Mineralogy and Optical Mineralogy. Chantilly, VA: ISBN 978-0-939950-81-2.
- Nesse, William D. (2000). Introduction to Mineralogy. New York: Oxford University Press. ISBN 9780195106916.
Further reading
- Hazen, R.M.; Grew, Edward S.; Origlieri, Marcus J.; Downs, Robert T. (March 2017). "On the Mineralogy of the 'Anthropocene Epoch'" (PDF). S2CID 111388809. Retrieved August 14, 2017. On the creation of new minerals by human activity.
External links
- Mindat mineralogical database, largest mineral database on the Internet
- "Mineralogy Database" by David Barthelmy (2009)
- "Mineral Identification Key II" Mineralogical Society of America
- "American Mineralogist Crystal Structure Database"
- Minerals and the Origins of Life (Robert Hazen, NASA) (video, 60m, April 2014).
- The private lives of minerals: Insights from big-data mineralogy (Robert Hazen, 15 February 2017)