Phlogopite
| Phlogopite | ||
|---|---|---|
2V angle 16–20° | | |
| Other characteristics | Fluorescent | |
| References | [2][3][4][5] | |
Phlogopite is a yellow, greenish, or reddish-brown member of the
Phlogopite is the magnesium
Paragenesis
Phlogopite is an important and relatively common end-member composition of biotite. Phlogopite micas are found primarily in igneous rocks, although it is also common in contact
The occurrence of phlogopite mica within igneous rocks is difficult to constrain precisely because the primary control is rock composition as expected, but phlogopite is also controlled by conditions of
Basaltic association
The basaltic occurrence of phlogopite is in association with picrite basalts and high-alumina basalts. Phlogopite is stable in basaltic compositions at high pressures and is often present as partially resorbed phenocrysts or an accessory phase in basalts generated at depth.
Ultrapotassic association
Phlogopite mica is a commonly known phenocryst and groundmass phase within ultrapotassic igneous rocks such as lamprophyre, kimberlite, lamproite, and other deeply sourced ultramafic or high-magnesian melts. In this association phlogopite can form well preserved megacrystic plates to 10 cm, and is present as the primary groundmass mineral, or in association with pargasite amphibole, olivine, and pyroxene. Phlogopite in this association is a primary igneous mineral present because of the depth of melting and high vapor pressures.
Ultramafic rocks
Phlogopite is often found in association with ultramafic intrusions as a secondary alteration phase within
Uses
As the general thermal, electrical and mechanical properties of phlogopite are those of the mica family, the main uses of phlogopite are similar to these of muscovite.
Miscellaneous
The largest documented single crystal of phlogopite was found in Lacey mine, Ontario, Canada; it measured 10 m × 4.3 m × 4.3 m and weighed about 330 tonnes.[7] Similar-sized crystals were also found in Karelia, Russia.[8]
References
- S2CID 235729616.
- ^ Mineralienatlas
- ^ Phlogopite WebMineral
- ^ http://rruff.geo.arizona.edu/doclib/hom/phlogopite.pdf Handbook of Mineralogy
- ^ http://www.mindat.org/min-3193.html Mindat
- ISBN 978-3-319-90223-4.
- ^ P. C. Rickwood (1981). "The largest crystals" (PDF). American Mineralogist. 66: 885–907.
- ^ "The giant crystal project site". Archived from the original on 2009-06-04. Retrieved 2009-06-06.
Further reading
- Deer, W.A., Howie, R.A., and Zussman, J., (1963). Rock-forming minerals, v. 3, "Sheet silicates", p. 42–54.
- Spencer, Leonard James (1911). . In Chisholm, Hugh (ed.). Encyclopædia Britannica. Vol. 21 (11th ed.). Cambridge University Press. p. 447.
