Apatite on Calcite with Pyroxene
Otter Lake District
Quebec, Canada

This crystal measures 7.5cm x 1.5cm


Apatite     Ca5(PO4)3(F,Cl,OH)

Phosphates; calcium fluorine-chlorine-hydroxl phosphate, often with some manganese and cerium

Color and Luster: Green, brown, red, yellow, violet, pink, white, colorless; greasy, vitreous; streak white

Hardness: 5

Cleavage: Poor, one direction crosswise

Fracture: Uneven

Crystals: Hexagonal; usually short to long prismatic; frequently tabular; also massive, coarse granular to compact stalactitic, earthy, oolitic


Calcite      CaCO3

Carbonate; calcium carbonate

Color and Luster: White, colorless, pale shades of gray, yellow, red, green, blue, brown to black when impure; vitreous, dull; streak white

Hardness: 3

Cleavage: Perfect in 3 directions, forming a rhombohedron

Fracture: Conchoidal, seldom observed

Crystals: Hexagonal; crystals commonly showing a rhombohedron, scalenohedron, and prism; also tabular, acicular, cleavable, granular, compact, stalactitic, oolitic, earthy; twinned crystals very common

Note: Apatites from this district are generally fluorapatites

Photo by Mary Sutherland


Descriptions taken from
The Audubon Society Field Guide to North American Rocks and Minerals