MINERALS • WHAT ARE THEY??
MINERALS • The basic materials of the earth’s crust. • The “building blocks” of rocks • Thousands are known • But only about 20 are common in the crust – these are the rock-forming minerals.
WHAT MAKES SOMETHING A MINERAL?? 4 THINGS NEEDED: • Must be “inorganic” – not made from living (or once-living) things. • Must occur naturally (not made by people). • Must be a solid, “crystalline” material. • Must have a “definite chemical composition”.
For example – Here’s a piece of granite rock, and the three minerals that it is made of.
COAL CONCRETE GOLD STEEL SALT (HALITE) OIL SO – WHICH OF THESE ARE MINERALS?
COAL CONCRETE GOLD STEEL SALT (HALITE) OIL SO – WHICH OF THESE ARE MINERALS? NO!! NO!! YES!! NO!! YES!! NO!!
mica quartz feldspar silver gypsum pyrite TWO MAIN GROUPS OF MINERALS • SILICATES (96%) Contain silicon (Si) and oxygen (O), plus other elements, usually • NON-SILICATES (4%) 6 major groups – see pp. 158-159