Bellringer: Sort these items into minerals and not minerals: Wood Sulfur Feldspar Fossil Granite Gold Copper Halite Ice Water Talc Topaz Dirt Smoke Sun

What is a Mineral?

What is a mineral? Properties: Solid Cannot be a liquid or a gas Naturally Occurring Found in nature, not man-made Inorganic Is not alive and never was, non-living Fixed composition Has a chemical formula, most are formed from compounds of two or more elements, some minerals consist of one element ex. Au Crystal Form A definite structure in which atoms are arranged

What is a mineral? Definition: A mineral is a naturally formed, inorganic solid that has a definite crystalline structure. -Questions to ask yourself when determining if an item is a mineral or not: Is it non-living material? Is it a solid? Is it formed in nature? Does it have a crystalline structure?

Minerals are identified by their key characteristics hardness crystal shape (form) luster color Streak Density (specific gravity) Cleavage/fracture special properties --reaction to acid --fluorescence --salty taste --magnetism

Hardness Refers to "scratchability" or resistance to being scratched. Harder minerals will scratch softer minerals. Geologists rank minerals according to hardness using the Moh's scale Moh's Hardness Scale 1.0     TALC 2.0    GYPSUM 2.5 FINGERNAIL 3.0    CALCITE 3.5    COPPER PENNY 4.0    FLUORITE 5.0    APATITE 5.5    STEEL KNIFE/GLASS PLATE 6.0    FELDSPAR 7.0    QUARTZ 8.0     TOPAZ 9.0     CORUNDUM (RUBY) 10.0 DIAMOND

Crystal Shape (Form) External structure due to internal arrangement of the atoms

Luster Describes how light reflects off the surface Main categories are “metallic” and “non- metallic” Non-metallic includes “dull,” glassy,” waxy,” “pearly,” and others

Non-metallic mineral Metallic mineral

Cleavage and Fracture -Cleavage refers to the pattern of very smooth, flat, or reflective surfaces that a mineral “cleaves” or breaks into. -These special breakage surfaces correspond to zones of weak bonding in the crystal structure. -Other minerals break unevenly along rough or curved surfaces--this is called fracture   NO cleavage

Color -Color results from ability to absorb some wavelengths and reflect others -some minerals have characteristic color while others vary due to chemical differences or impurities (rust, other mineral, etc.) e.x. quartz -VERY unreliable.

Streak Color of the powder when rubbed on a “streak plate” (unglazed porcelain) Always the same unlike color.

Density (Specific Gravity) density (mass /volume) Specific Gravity is the density of the mineral compared with density of water

Special Characteristics-- Fluorescence Some minerals will glow when placed under ultraviolet light Carbonates react with dilute HCl and other acids by fizzing or bubbling (releasing CO2 gas) The “Acid Test”

Special Characteristics-- Salty Taste DO NOT TASTE MOST MINERALS! Halite is the exception--it will taste salty

Special Characteristics-- Magnetism Many iron minerals will produce an invisible magnetic force field