| A | B |
|---|
| mineral | naturally occurring, inorganic solid with a definite chemical composition and an orderly arrangement of atoms |
| four thousand | minerals on Earth |
| crystal size | how fast or slow crystals cool |
| silicon and oxygen | two most abundant elements in the Earth's crust |
| hardness | how easily a mineral scratches |
| diamond | hardest mineral |
| talc | softest mineral |
| luster | the way minerals reflect light |
| streak | color of a mineral when it is in powdered form |
| cleavage | minerals break in nice smooth angles |
| fracture | minerals break with rough uneven edges |
