Rubicline

Source: Wikipedia, the free encyclopedia.
Rubicline
Formula mass
313.11 g/mol
ColorColorless
Cleavage{001}
LusterVitreous
DiaphaneityTransparent
Density2.8 g/cm3
Optical propertiesbiaxial
Refractive indexnα = 1.520 nβ = 1.524 nγ = 1.527
Birefringenceδ = 0.007
DispersionStrong
Other characteristicsRadioactive
References[2][3]

Rubicline, also referred to as Rb-microcline, is the

tectosilicate mineral. Its chemical formula is (Rb, K)[AlSi3O8] with an ideal composition of RbAlSi3O8. Chemical analysis by electron microprobe indicated the average weight of the crystal is 56.66% SiO2, 16.95% Al2O3, and 23.77% Rb2O,[4] along with trace amounts of caesium oxide (Cs2O) and iron(III) oxide (Fe2O3).[5]

Rubicline was first discovered in 1998 in Elba, Italy, by a team from the University of Manitoba. It was the first mineral to have been discovered with rubidium as an essential constituent.[5] It has also been found in Mozambique[6] and the Kola Peninsula in Russia.[7] Rubicline occurs as small, abundant, rounded grains found within veins of rubidian microcline. Pure rubicline with an ideal potassium-free composition has never been found in nature.[4] Rubicline was synthesized in 2001 by placing powdered albite in a solvent of RbCl. This mixture was then placed in a silver tube containing H2O, heated to 400 °C and pressurized to 60 MPa.[4]

Unlike microcline, which can be yellow, red, or green, rubicline is colorless. It is also

adularia, anorthoclase, buddingtonite, celsian, hyalophane, microcline, monalbite, orthoclase, and sanidine.[8]

Like all rubidium compounds, rubicline is mildly

radioactive. Activity and dose rate of various amounts of rubicline are listed in the table below.[2]

Specimen weight/size Calculated
activity (Bq) 		Calculated
activity (Ci) 		Estimated
activity GR(api) 		Estimated
exposure (
mRem
)/hr*
1000 g / 8.79 cm 183,355 4.96×10−6 8,449.31 2.78
100 g / 4.08 cm 18,336 4.96×10−7 844.93 0.28
10 g / 1.89 cm 1,834 4.96×10−8 84.49 0.03
1 g / 8.79 mm 183 4.96×10−9 8.45 0.00
0.1 g / 4.08 mm 18 4.96×10−10 0.84 0.00
0.01 g / 1.89 mm 2 4.96×10−11 0.08 0.00
0.001 g / 0.88 mm 0 4.96×10−12 0.01 0.00
  • If held in hand for one hour.
  • Government estimate of average annual exposure (360 mRem)
  • Max permissible adult dose 50,000 mRem/yr (hands), 15,000 mRem/yr (eyes)
  • Lethal exposure 400,000 to 500,000 mRem

References

  1. S2CID 235729616
    .
  2. ^ a b Rubicline at Webminerals
  3. ^ Rubicline at Mindat
  4. ^
    S2CID 95219083
    .
  5. ^
    doi:10.2138/am-1998-11-1223
    .
  6. S2CID 53607085
    .
  7. ^ "Rubicline R070044". RRUFF. Retrieved 15 February 2010.
  8. ^ a b c Ralph, Jolyon & Chau, Ida (2010). "Rubicline". Mindat.org. Retrieved 15 February 2010.
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