ISCI 1A24 Lecture Notes - Lecture 2: Clay Minerals, Hematite, Montmorillonite
29 Sep 2016
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Document Summary
Most important rock-forming minerals contain silicon and oxygen form silicates. 90% of minerals in earth"s crust fall into 5 groups of silicates: Most common on earth"s surface calcite (caco3) Ore minerals magnetite, hematite (iron), galena (lead), sphalerite (zinc) Streak colour when mineral is ground to a fine powder ex. hematite (red/brown), silicate minerals do not streak. Lustre reflection of light from mineral surface, metallic or non-metallic. Hardness (scratchability) moh"s hardness scale (1-10), talc = 1, diamond = 10. Cleavage ability of a mineral to break along preferred directions when struck. Fracture surface along which a mineral breaks, not controlled by cleavage (conchoidal = rounded) Specific gravity way to express density, ratio of density of mineral:water, water rho = 1. Magnetism some minerals are magnetic, while others are not. Rocks change from one type to another with time through the rock cycle. Rock naturally-formed, consolidated material composed of grains of one or more minerals vs.
