"Classroom Minerals"

Spinel group; black, dull metallic luster; common iron oxide.

Feldspar group; good cleavages of pure soda lime feldspar; most show twinning and labradorescence.

Good grade, brass-yellow copper ore, massive.

Bright blue crystalline veins and coatings in a matrix of mixed copper ore.

Clear rhombs showing double refraction.

Pyroxene group; dark green, pure cleaved fragments.

Pure translucent to white, rhombic cleavages, Mohs’ hardness of 3.

Coarse, 'salt and pepper': dark pyroxene and light andesine. Provides perfect representation of an intermediate igneous rock.

Cut black mica cleavage sheets.

Feldspar group; pink cleavages showing perthitic texture, common potassium feldspar, Mohs’ hardness of 6.

Feldspar group; white to gray, sodium plagioclase cleavages; some faces may show twinning.

Feldspar group; calcium end member plagioclase crystals in pyroxene matrix.