Geology Home Page
Roger Weller, geology instructor
Chemical Group: native element
Chemical Formula: C (carbon)
Color: colorless, pink, yellow, blue, brown, black, red Streak: too hard
Specific Gravity: 3.50
transparent to opaque (black)
Cleavage: octahedral, 4 directions
Crystal Forms and Habits:
The most common crystal form is and octahedron, often with rounded surfaces.
Diamonds may also crystallize as cubes or tetrahedrons.
Mineral Associations: ultrabasic igneous rocks (kimberlites)
Uses: gemstones, abrasives
Occurrences: South Africa, Siberia, Australia
Toxicity: when-swallowed- low when inhaled- moderate
Additional Information: diamond that is not gem quality is called bort.