| A | B |
|---|
| Graphite | used instead of lead in pencils |
| gypsum | principal component of plaster of Paris |
| flint | can be chipped to form sharp edges |
| mica has unique characteristic of... | forming large crystals which break into flat sheets |
| vermiclite | special kind of mica found in clay |
| mineral | forms special kind of solid called crystal |
| crystals have | flat surfaces and sharp edges |
| crystals have a definate shape because | their atoms are arranged in orderly fashion |
| geodes may be hollow or solid and | contain crystal formations made of calcite and quartz |
| gemstones are | rare, beautiful minerals which are very hard |
| Once they are cut, gemstones are called | gems |
| Most valued gems include | diamonds, rubies, emeralds, and sapphires |
| the hardest of all substances | diamonds |
| the rarest of all gemstones is the... | ruby |
| which gemstone can carry electric current? | quartz |
| a scale of hardness was developed by... | Friedrich Mohs |
| an industrial use for rubies | lasers |
| an industrial use for diamonds | can cut through metal,glass, &other stone |
| mineralologists | scientists who study minerals |
| a minerals general appearance | its "habit" |
| a minerals ability to reflect light | its "luster" |
| the way a mineral fractures or breaks | cleavage |
