Earth Sciences 1081A/B Study Guide - Final Guide: Lava Dome, Metamorphism, Conchoidal Fracture
16 Apr 2014
School
Department
Course
Professor
Document Summary
9 orthoclase (potassium feldspar) creamy pink color plagioclase (sodium/calcium feldspar) tends to be white or grey specific gravity: minerals with metallic lustre: heavier than non metallic lusters. Four intersecting cleavage directions will ideally produce an 8-sided polyhedron (thus octahedral cleavage)- whoa, this is as complex as we"ll go for now! Three cleavage directions intersecting at 900 (right angles) produces a cube (thus cubic cleavage), whereas three cleavage directions not intersecting at. 900 produce what looks like a leaning box - a rhombohedron (thus rhombohedral cleavage). A few minerals do not exhibit cleavage when broken, but rather fracture in a non-planar (but still distinctive) way. Sedimentary rocks composed of sediment-materials deposited at or near earth"s surface by the settling out of air or water. Texture phaneritic: interlocking crystals are large enough to see without magnification help aphanatic texture: constituent crystals are too small to be easily observed without magnification help.
