Geology Home Page
Roger Weller, geology instructor
Chemical Group: sulfide
Chemical Formula: FeS2
Color: pale bronze-yellow, darkens on exposure to air
Streak: grayish black to brownish black
Hardness: 6 to 6.5
Specific Gravity: 4.89
Cleavage: (101), distinct
Twinning is quite common and produces "cockscomb structures".
May also occur as shiny, flat disks that form betwwen layers of shale.
Mineral Associations: galena and sphalerite
Identifying Characteristics: crystal shape (cockscomb)
Occurrences: found in near surface environments; less stable than pyrite
Toxicity: when-swallowed- moderate when inhaled- moderate