Görgeyite

Görgeyite is a sulfate that is very rare that is usually present in evaporite deposits. It’s a gem that is acutely unusual crystals are extremely rare. Görgeyite is hardly radioactive because of the amount that is small of in its chemistry.

The source that is only of quality crystals is Inder Lake, Atyrau Oblast’, Kazakhstan.

Chemical Formula:	K2Ca5(SO4)6·(H2O)
	Hydrated Potassium Calcium Sulfate
Molecular Weight:	872.98 gm
Composition:	Potassium 8.96 % K 10.79 % K2O Calcium 22.95 % Ca 32.12 % CaO Hydrogen 0.23 % H 2.06 % H2O Sulfur 22.04 % S 55.03 % SO3 Oxygen 45.82 % O   100.00 % 100.00 % = TOTAL OXIDE

 

Crystallography:	Monoclinic – Prismatic
Crystal Habit:	As crystals, tabular on {001}, to 8.5 cm, showing {001}, {100}, {111}, {110}.
Twinning:	None

 

Cleavage:	[100] Imperfect
Fracture:	Splintery to Hackly
Tenacity:	Brittle
Moh’s Hardness:	3.5 – 4.0
Density:	2.90 – 2.93 (g/cm3)
Luminescence:	None
Radioactivity:	Barely Detectable; GRapi = 129.09 (Gamma Ray American Petroleum Institute Units)

 

Color:	Colorless, White, pale Yellow, Greenish Yellow
Transparency:	Translucent to Transparent
Luster:	Vitreous
Refractive Index:	1.560 – 1.585  Biaxial ( + )
Birefringence:	0.0240
Dispersion:	None
Pleochroism:	None