Ch. 13 Minerals • Minerals are naturally formed solids with a crystalline structure • Minerals are made of atoms and compounds • Crystals have definate shapes • EXAMPLE: Table salt (NaCl) has a definate shape and is made of two elements
Silicate vs. Nonsilicate • Silicate minerals make up 90% of the Earth’s surface; have a combo. Of oxygen, silicon and at least one metal like iron or aluminum. • Nonsilicate minerals do not have the silicon-oxygen combo.
Properties • Color • Luster: how dull or shiny; different types on p. 340 • Streak: using a streak plate, the mineral may leave a different color powder when pulled across the plate • Cleavage and Fracture: how the mineral breaks (important in jewelry) • Mohs Hardness Scale: ranges from 1 (soft) to 10 (hard); does NOT have a set measurement • Density: used to compare the minerals to water