Gypsum

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

Gypsum Properties

Chemical Composition: 
Hydrated calcium sulphate
Crystal System / Forms: 
Monoclinic
Hardness: 
2
Specific Gravity: 
2.32
Lustre: 
Silky to vitreous.
Refractive Index / Birefringence: 
1.52-1.53 / 0.010
Magnification: 
  • In rough, parallel fibrous structure.
  • In cabochon, stain lustre.
Geological Occurrence: 
Italy and England (Alabaster); Italy, Mexico, the United States and Chile (Selenite).
Cuts & Uses: 
Cabochon