GEOL 101 Lecture Notes - Lecture 4: Conchoidal Fracture, Orthoclase, Plagioclase
18 Oct 2016
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Document Summary
Snowflake crystals ice minerals form with six symmetrical sides. Mineral: naturally occurring inorganic solid, ordered internal molecular structure, definite chemical composition, about 5000 different minerals found throughout earth or from meteorites, crystal form. An external expression of a minerals internal structure. Often not able to develop because of limited space and/or rapid loss of heat: polymorphs. Minerals that have the same composition but different crystalline structures. Ex. diamonds and graphite are both formed from carbon but are extremely different: mineral groups. Make up most rock-forming minerals (very abundant due to large amounts of oxygen and silicon in earth"s crust) Contain silicon-oxygen tetrahedron (4 oxygen ions surrounding silicon ions) Common silicate minerals feldspar group (most common) Only common silicate composed entirely of oxygen and silicon. Often forms hexagonal crystals: mica group. Used on stoves/windows b/c it is see-through but will not melt like glass. Produces the glimmering that is often seen in beach: olivine group sand.
