1. Minerals Minerals are naturally-occurring inorganic solids that possess a definite chemical structure. -Over 4000 different minerals on Earth -Must have the following characteristics: Naturally occurring, inorganic, solid and definite chemical structure

2. Building Blocks of Minerals Basic building blocks of minerals: -Elements – 118 elements known; usually more than two elements combine to make a mineral. -Protons – positive charge -Electron – negative charge -Neutrons - neutral

3. Properties of Minerals Crystal form – external expression of a mineral’s internal orderly arrangement of atoms. Luster – appearance or quality of light reflected from the surface of a mineral. Color – obvious feature but unreliable in identification.

4. Mineral Properties Cont. Streak – color of a mineral in its powdered form. (you rub them on unglazed porcelain) Hardness – measure of the resistance of a mineral to abrasion or scratching. Cleavage – tendency of a mineral to cleave, or break along planes of weak bonding. Fracture – most minerals fracture irregularly

5. Mineral Properties Cont. Specific Gravity – compares the weight of a mineral to the weight of an equal volume of water. Other properties: - taste, malleability, elasticity, touch, magnetic, double refraction and reaction to HCL.

6. Mineral Groups Silicates (most common) basic building block of all silicates is silicon-oxygen tetrahedron. -olivine, hornblende, micas, feldspars, quartz Non-silicate (scarce) - oxides, sulfides, sulfates, halides