EARTHSC 1108 Lecture Notes - Lecture 1: Sapphire, Aluminium Oxide, Ruby
5 Apr 2016
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Document Summary
Alluvial deposits that contain significant amounts of metals and gems. Properties of metals and gems properties of placer minerals: High mechanical durability = hard history of names beryl: from ancient greek, beryl"s, originally applied to all green stones. Some important locations: columbia, brazil, madagascar, tanzania, austria, russia, namibia, Zambia, nigeria, egypt (ancient source of emeralds that is now depleted) States include colorado, idaho, maine, north carolina, & california. Located in the andes mountains of south america, rugged terrain. West coast of south america is bordered by a subduction zone. Host rocks for emeralds are strongly deformed sedimentary rocks (folded and fractured) Hydrothermal fluids penetrated the cracks in the deformed sedimentary rocks. Veins of calcite concentrated in layers gemstones from the pegmatites of minas gerais, No subduction in the east coast of south america. Brazil feels the magma regime from the other side of the continent, develops pegmatites. Largest gem bearing pegmatite district in the world.
