"gray K. Besonson"

Geometric Shapes and Structures of Crystalline Minerals.

Good grade, brass-yellow copper ore, massive.

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

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

Feldspar group; greenish gray alkali feldspar, coarse crystalline, some iridescence.

Classic “peacock” aluminum ore.

Cut black mica cleavage sheets.

Clear rhombs showing double refraction.

Black, high grade, foliated, greasy feel.

Clear, pure cleavages, Mohs’ hardness of 2.

Black, Micaceous, glittery metallic.

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

Spinel group; iron-black, massive; natural magnet.

Good grade, green, massive; copper ore.

Mica group; cut sheets showing basal cleavages. Books and sheets in bulk pack.

Feldspar group; white-to-gray cleavages of sodic plagioclase; some show twinning.