Feldspar group; white-to-gray cleavages of sodic plagioclase; some show twinning.
A classroom set that covers the major types of coal.
Clear rhombs showing double refraction.
Classic, white chalk, massive; from Cliffs of Dover, England.
Crystals and crystal sections up to 1", Mohs’ hardness of 9.
Pure, large, transparent-to-translucent cleavages, Mohs’ hardness of 4.
Bright metallic cubic cleavages; lead ore.
Black, high grade, foliated, greasy feel.
White, fine, massive, opaque to slightly translucent.
White, fibrous, silky luster.
Clear, pure cleavages, Mohs’ hardness of 2.
Himalayan mineral great for teaching and display.
Red, classic oolitic texture.
Black, Micaceous, glittery metallic.
Pure, white, earthy “China clay”.
Brown, earthy, massive; used for yellow pigment.
