Cochise College          Photos of Minerals

                          Geology Home Page                

                          Roger Weller, geology instructor

                          wellerr@cochise.edu
                                  copyright 2006-R.Weller
 

Mineral Information on:
staurolite

Chemical Group:    silicate

Chemical Formula:   
HFeAl5Si2O13

Color:  brown            Streak:  gray       Luster:  vitreous to sub-resinous

 

Hardness:  7            Specific Gravity:  3.7 to 3.8             Fracture:

Cleavage:  distinct cleavage in one direction

 

Crystal Forms and Habits:  Monoclinic system
     Staurolit commonly forms interpenetration twins, either at a 60 degree angle
     or at a 90 degree angle.

Mineral Associations:  a metamorphic mineral, often found in mica schist

Identifying Characteristics:  Staurolite does form single crystals, but twinned crystals
     make the reputation for this mineral.

Uses:  The right angle twins are used in jewelry and are marketed as "fairy crosses".

Occurrences:  Georgia, Virginia 

Toxicity:      when-swallowed- low        when inhaled- high

Additional Information: