Cochise College          Photos of Minerals

                          Geology Home Page                

                          Roger Weller, geology instructor

                          [email protected]
                                  copyright 2006-R.Weller
 

Mineral Information on:
orpiment

Chemical Group:    sulfide

Chemical Formula:    As₂S₃

Color:  lemon-yellow to brownish yellow                Streak: pale yellow

Luster:  pearly, resinous         Transparency:  transparent

Hardness:  1.5 to 2        Specific Gravity:   3.49                

Cleavage:  one direction                Tenacity:  brittle

Crystal Forms and Habits:  Monoclinic system
     Crystals are usually small.
     Orpiment often occurs in foliated, columnar, or fibrous masses.

Mineral Associations:  Commonly occurs with realgar, stibnite, calcite, gypsum, barite.

Identifying Characteristics:

Uses:  arsenic ore

Occurrences: 

Toxicity:      when-swallowed- very high        when inhaled- very high

Additional Information: