Sulfates and Chromates

The basic unit of the sulfate minerals are the SO4 groups. These groups combine with metals to form the sulfate minerals. Barite, gypsum, and anhydrite are the most common sulfate minerals.

Minerals of the sulfate class:

  • Have vitreous luster.
  • Have average to above average density.
  • Have average hardness.
  • Originally formed in veins, oxidation zones, contact metamorphic zones and evaporite deposits.
  • Are, in some cases, soluble.
  • Are, in several cases, fluorescent.

Minerals

Alunite
Anglesite
Antlerite
Barite
Celestite
Chalcanthite
Crocoite
Gypsum

Mineral Photos courtesy of R.Weller/Cochise College