Geology Home Page
Roger Weller, geology instructor
Chemical Group: carbonate
Chemical Formula: CaCo3
Color: colorless, white, gray, red, green, blue, violet, yellow,
Luster: vitreous to sub-vitreous to earthy
Streak: white to grayish Transparency: transparent to opaque
Specific Gravity: 2.710
Cleavage: rhombohedral, 3 directions
Crystal Forms and Habits:
Calcite crystallizes in a wide variety of modified rhombohedrons and scalenohedrons.
Calcite occurs in many forms: massive, stalactitic, fibrous, earthy, layered, etc.
Identifying Characteristics: Reacts strongly with dilute hydrochloric acid: bubbles of CO2 are released.
A clear variety of calcite (Iceland Spar) displays double refraction.
Occurrences: All over the world, but crystals are more commonly in vugs in limestones.
Toxicity: when-swallowed- low when inhaled- low