MINERAL IDENTIFICATION HELP SHEET
| MINERAL NAME | LUSTER (appearance) | HARDNESS | DISTINGUISHING PROPERTIES |
| Pyrite | Metallic | Slightly harder than glass | Hardness greater than glass (H ~ 6-6.5); Brassy yellow color; black streak; Crystals commonly cubic; no cleavage. |
| Galena | Metallic | Softer than glass | 3 perfect cleavages at 90 degrees, high density. |
| Hematite | Metallic or non-metallic luster | Hard to tell, but harder | Red-brown streak. |
| Hornblende | Non-metallic (black) | Harder than glass | Usually black or dark green; 2 cleavages at 60°/120° (56°/124°) |
| Biotite | Non-metallic (black) | Slightly harder than glass | 1 perfect cleavage; Dark brown-black color, faint yellow-brown streak. |
| Olivine | Non-metallic (green) | Slightly harder than glass | Olive green color; Granular; Conchoidal fracture; Hardness greater than glass (H ~ 6.5 – 7). |
| Plagioclase Feldspar | Non-metallic (med. grey to light grey) | Slightly harder than glass | 2 cleavages at about 90°; Striations (twinning) present; can be white to dark gray. |
| Potassium Feldspar | Non-metallic (Pink to white) | Slightly harder than glass | 2 cleavages at about 90°; Striations not present; can be pink, white (sometimes green). |
| Quartz | Non-metallic (any color) | Harder than glass | Hexagonal crystals; No cleavage planes; Conchoidal Fracture; Hardness greater than glass (H=7 on Moh’s scale). |
| Muscovite | Non-metallic (gold-clear) | Softer than glass | 1 perfect cleavage; Colorless or silvery appearance, once used for window glass; Ke$ha likes it. |
| Fluorite | Non-metallic (purple, green, yellow) | Softer than glass | softer than glass; FOUR cleavage planes! |
| Calcite | Non-metallic | Softer than glass | 3 perfect cleavages not at 90° (rhombohedral cleavage); Fizzes readily when HCl acid applied. |
| Halite | Non-metallic | Softer than glass | 3 perfect cleavages at 90°; Tastes like salt, feels greasy. |
| Gypsum | Non-metallic | Softer than glass and softer than a fingernail | Generally clear to white; One perfect cleavage, may show up to 3 cleavages; Easily scratched with a fingernail. |
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