Gypsum

gypsum
Gypsum in brown mineral

Several varieties of gypsum are used as decorative stones. The most  important, alabaster, is found as fine-grained masses in pastel shades, but is commonly stained in stronger colors.

Selenite is colorless, occasionally cut for collectors, but very soft. Satin spar is a fibrous variety, polished or cut in cabochon. Rose shapes (called “desert rose”) also occur. Gypsum also comes in cat’s eye effect.

Localities include Italy and England (Alabaster); Italy, Mexico, United States and Chile (Selenite).

Gypsum Pictures

Rough gypsum

Chemical Composition :

Hydrated calcium sulphate


Crystal System / Forms :

Monoclinic


Cuts & Uses :

Cabochon


Hardness : 2
Lustre : Silky to vitreous.
Magnification :
  • In rough, parallel fibrous structure.
  • In cabochon, stain lustre.

Refractive Index / Birefringence :

1.52-1.53 / 0.010


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