EQ: What are the properties of a mineral? Minerals EQ: What are the properties of a mineral?
Definition Naturally occurring Inorganic (non living) Solid Definite chemical composition Crystalline structure Arrangement of ions Used for identification Example: diamond vs. coal/graphite
Diamond vs. coal
Mineral Formation Almost all minerals form from magma, the molten rock beneath the earth’s surface. When magma cools, mineral crystals are formed.
When magma cools slowly, large crystals form.
When magma cools rapidly, small crystals form.
When magma cools very, very quickly on the earth’s surface, no crystals will form at all.
Mineral identification Color Sulfur- yellow Pyrite- fool’s gold Azurite- blue Malachite- green
Mineral Identification Can’t use: Different minerals can have the same color Some minerals have different colors. Minerals can change color over time through weathering.
Moh’s Scale of hardness Talc-easily scratched with fingernail Gypsum-scratched with fingernail Calcite-scratched with copper penny Fluorite-scratched with steel nail Apatite-easily scratched with steel nail Feldspar-scratches glass with force Quartz-scratches glass with moderate force Topaz-scratches glass with minimal force Corundum-scratches glass easily Diamond-cuts glass
streak The powder left behind when a mineral is rubbed on an unglazed ceramic tile. Metal- dark streak Non metal- light streak Non metal- no streak
Luster The way a mineral reflects light Glassy Greasy Earthy Metallic pearly
What is the luster of this mineral?
What is the luster of this mineral?
What is the luster of this mineral?
What is the luster of this mineral?
What is the luster of this mineral?
Cleavage A tendency of a mineral to split along an even plain. One directional Peels off in layers Example- biotite and muscovite.
cleavage Two directional Flat and shiny plains Example: feldspar
cleavage 3 directional Calcite and halite 4 directional fluorite
The uneven splitting of a mineral. Fracture The uneven splitting of a mineral.
Magnetism Is the mineral magnetic? Example: magnetite
Hydrochloric acid makes the mineral fizz. Acid test Hydrochloric acid makes the mineral fizz.