Kainosite-(Y)

Kainosite
General
Category	Silicate mineral
Formula (repeating unit)	Ca2(Y,Ce) SiO4O12(CO3)•(H2O)
IMA symbol	Kno-Y[1]
Crystal system	Orthorhombic
Crystal class	Dipyramidal (mmm) H-M symbol: (2/m 2/m 2/m)
Space group	Pmnb
Identification
Formula mass	664.14 g/mol
Colour	Variable, from brown and yellow to colourless
Cleavage	{110} Good
Fracture	Brittle and uneven
Mohs scale hardness	5–6
Lustre	vitreous to resinous
Streak	White
Diaphaneity	Transparent to translucent
Optical properties	Biaxial (-)
Refractive index	nα = 1.662–1.665 nβ = 1.682–1.689 nγ = 1.687–1.692
Birefringence	Maximum Birefringence: δ = 0.025–0.027
2V angle	Measured: 40°, Calculated: 38° to 52°
Dispersion	strong
Other characteristics	high relief

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^[2] and was named by Adolf Erik Nordenskiöld (1832–1901) in allusion to the Greek word for "unusual" for its rarity and exotic composition.^[3]

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. Classic samples have been discovered in Madawaska Mine, Bicroft Mine, and Greyhawk Mine, near Bancroft, Ontario.^[4]