Cochise College          Photos of Minerals

                          Geology Home Page                

                          Roger Weller, geology instructor

                                  copyright 2005-R.Weller

Mineral Information on:

Chemical Group:    carbonate

Chemical Formula:   

Color: ash-gray, yellowish gray, greenish gray, brown,
     reddish brown                                                                         

Streak:  white         Transparency:  translucent to sub-translucent


Hardness:  3.5 to 4         Specific Gravity:  3.83 to 3.88                 

Fracture:  uneven to sub-conchoidal

Luster:  vitreous to pearly

Cleavage:   rhombohedral cleavage, 3 directions


Crystal Forms and Habit:  Trigonal system
     Crystal shapes are primarily rhombohedrons.
     Crystal surfaces might be curved similar to dolomite.
     Commonly found in cleavable masses.
     May also occur in botryoidal forms, or compact, or earthy.

Mineral Associations:

Identifying Characteristics:  May resemble some sphalerite, but unlike sphalerite, can be attacked
     by concentrated hydrochloric acid.

Uses:   iron ore

Occurrences:  Roxbury, Connecticut 

Toxicity:      when-swallowed- moderate         when inhaled- moderate

Additional Information: