Vishnevite Explained

Vishnevite
Category:	Tectosilicate
Formula:	(Na,Ca,K)6(Si,Al)12O24[(SO<sub>4</sub>),(CO<sub>3</sub>),Cl<sub>2</sub>]2-4·nH2O
Imasymbol:	Vhn^[1]
Strunz:	9.FB.05
System:	Hexagonal
Class:	Pyramidal (6) H-M symbol: (6)
Symmetry:	P63
Unit Cell:	a = 12.7228(3) c = 5.198(3) [Å]; Z = 1
Color:	Colorless, light blue, orange-yellow, white
Cleavage:	Perfect
Mohs:	5 - 6
Luster:	Vitreous, pearly
Streak:	White
Opticalprop:	Uniaxial (-)
Refractive:	nω = 1.490 - 1.507 nε = 1.488 - 1.495
Birefringence:	δ = 0.002 - 0.012

Vishnevite, or sulfatic cancrinite, is a mineral of the cancrinite group with the chemical formula (Na, Ca, K)₆(Si, Al)₁₂O₂₄[([[sulfur|S]]O₄),(CO₃), Cl₂]_2-4·nH₂O. It has hexagonal crystals.^{[2] [3]}

External links

• Mindat data

Notes and References

1. Warr. L.N.. 2021. IMA–CNMNC approved mineral symbols. Mineralogical Magazine. 85. 3. 291–320. 10.1180/mgm.2021.43. 2021MinM...85..291W. 235729616. free.
2. Fleischer, Michael & Mandarino, Joseph, "Glossary of Mineral Species", The Mineralogical Record, 1991
3. http://www.webmineral.com/data/Vishnevite.shtml Webmineral data