Minerals Naturally occurring Inorganic= not from living materials. Solid= particles pack tightly together. Crystal structure= particles line up in repeating patterns. Definite chemical composition= contains certain elements in the same proportions.

Identifying Minerals Each mineral has its own characteristic that can be used to identify it. Hardness Color Streak Luster Density Crystal shape Cleavage and Fracture

Crystal Structure A crystal is a solid in which the atoms are arranged in a pattern that repeats again and again. It is sort of like a repeating wallpaper pattern.                                                                                                                    

Birthstones January - Garnet July - Ruby February - Amethyst August - Peridot March Aquamarine September Sapphire April – Diamond October - Opal May – Emerald November - Topaz June - Pearl December - Turquoise

Hardness Mohs hardness scale Ranks ten minerals from softest to hardest based on their ability to be scratched. Any mineral harder can scratch a softer mineral but a softer mineral can not scratch a harder mineral.

Mohs Hardness Scale Minerals are ranked by hardness on a scale of 1(softest/graphite) to 10 (hardest/diamond). The scale is based on a scratch test.

Color Not a great identifying factor since many minerals are the same color and the same mineral can be different colors. All three of these are quartz.

Streak Color of the mineral powder. Observe by rubbing on a streak plate.

Luster Ability to reflect light. Dull to shiny Metallic luster

Density All minerals have a distinct density.

Crystal Shape Mineral are grown atom by atom so each mineral has the same crystal shape. Six groups = cubic, hexagonal, tetragonal, orthorhombic, monoclinic, triclinic. Triclinic Tetragonal

Cleavage and Fracture Cleavage = Easily splits along flat surfaces. Fracture = what a mineral looks like when it breaks apart.

Special Properties Fluorescence- some minerals glow under ultraviolet light ex.) Fluorite Magnetism- some metallic minerals are naturally magnetic ex.) Magnetite Effervescence- some minerals such as Calcite fizz when acid is placed on it Electrical Properties- a few minerals, such as quartz produce an electrical current

Earth Science Reference Tables