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Görgeyite
Current inventory:  0 gems
 

  
Görgeyite is named in honor of Rolf von Görgey (1886–1915), an Austrian mineralogist specializing in Austrian salt deposits.

Discovered in 1953;   IMA status: Valid (pre-IMA; Grandfathered).

Chemistry

Chemical Formula:

K₂Ca₅(SO₄)₆·(H₂O)

Hydrated Potassium Calcium Sulfate

Molecular Weight:

872.98 gm

Composition: 

Classification

Mineral Classification:

Sulfates

Strunz 8th Ed. ID:

29.4.7.1

Nickel-Strunz 10th Ed. ID:

7.CD.30

7 : SULFATES (selenates, tellurates, chromates, molybdates, wolframates)
C : Sulfates (selenates, etc.) without additional anions, with H₂O
D : With only large cations

Related to:

Polyhalite - Görgeyite Series

Synonyms:

Goergyite, Mikheevite, Mikheyevite

Crystal Data

Crystallography:

Monoclinic - Prismatic

Crystal Habit:

As crystals, tabular on {001}, to 8.5 cm, showing {001}, {100}, {111}, {110}.

Twinning:

None

Physical Properties

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)

Optical Properties

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

Occurances

Geological Setting:

Typically an uncommon secondary mineral in evaporite deposits; in hydrothermal veins.

Common Associations:

Anhydrite, Glauberite, Gypsum, Halite, Polyhalite, (evaporites); Cesanite, Pyrite (Cesano, Italy).

Type Locality:

Ischler Salzberg, Perneck, Bad Ischl, Upper Austria, Austria

Year Discovered:

1953

View mineral photos:

Görgeyite Mineral Photos and Locations

More Information

Mindat.org
Webmineral.com

Görgeyite is a ver rare sulfate mineral that is usually found in evaporite deposits. It is an extremely rare gem since crystals are very rare. Görgeyite is barely radioactive due to the small amount of Potassium in its chemistry.

The only source of gem quality crystals is Inder Lake, Atyrau Oblast', Kazakhstan.
  

  
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