Kainosite-(Y)

Kainosite is a silicate mineral that has the formula of Ca2(Y,Ce) SiO4O12(CO3)•(H2O). Kainosite was first discovered in Norway on the island of Hitterø[1] and was named by Adolf Erik Nordenskiöld (1832–1901) in allusion to the Greek word for "unusual" for its rarity and exotic composition.[2]

Kainosite
General
CategorySilicate mineral
Formula
(repeating unit)
Ca2(Y,Ce) SiO4O12(CO3)•(H2O)
Crystal systemOrthorhombic
Crystal classDipyramidal (mmm)
H-M symbol: (2/m 2/m 2/m)
Space groupPmnb
Identification
Formula mass664.14 g/mol
ColourVariable, from brown and yellow to colourless
Cleavage{110} Good
FractureBrittle and uneven
Mohs scale hardness5–6
Lustrevitreous to resinous
StreakWhite
DiaphaneityTransparent to translucent
Optical propertiesBiaxial (-)
Refractive indexnα = 1.662–1.665 nβ = 1.682–1.689 nγ = 1.687–1.692
BirefringenceMaximum Birefringence: δ = 0.025–0.027
2V angleMeasured: 40°, Calculated: 38° to 52°
Dispersionstrong
Other characteristicshigh relief

Kainosite, is part of the orthorhombic crystal class minerals, which is a system that results from stretching a cubic lattice along two of its orthogonal pairs. Kainosite is a biaxial mineral, so the light entering its crystals will be polarized in two vibration directions (XYZ) for it has two optic axes. Because Kainosite is orthorhombic, the vibration directions XYZ coincide with the a,b,c crystallography axes.

Kainosite is very rare and mostly found in Russia in vugs, pegmatites, granites, and alkalic complex as an altered product of the mineral kuliokite.


References

  1. Kainosite-(Y), WebMineral.com.Accessed 17 September 2010.
  2. Kainosite-(Y), MinDat.org
  • Rumanova I.M,and Volodina G.F,and Belov N.V (1967) "The crystal structure of the rare earth ring silicate kainosite, Ca2(Y,Tr)2[Si4O12]CO3[H2O]". Soviet Physics Crystallography, 11, 485–491.
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