Friday, January 28, 2011

Mineral Classes - Systematic Mineralogy


Minerals are divided up into different classifications by their chemical formulas.  These mineral classes are referred to as “systematic mineralogy”. 
The numbers in the chemical formulas are all subscript. 

Many mineral collectors base their collections of the mineral classes similarly to a library using the dewy-decimal system for cataloging books.

The classes are;
Native Elements: which are minerals made of only one element.  Minerals like diamond, sulfur, gold, silver, copper & graphite. 
Sulfides: Are minerals that have sulfur in their composition.  This class of minerals is made up of many of the important metal ores like Chalcocite/Bornite/Covellite which are copper minerals.  Cinnabar is mercury ore.  Orpiment & realgar are arsenic ores.  Molybdenite is molybdenum ore. There are many more.
Oxides: Are minerals that have oxygen in their composition.  (not part of water).  This class includes hematite as iron ore, corundum (rubies/sapphires), uraninite as uranium ore. Bauxite as aluminum ore.
Halides: are minerals that have Cl, Br, F, or I at the end of the formula.  The word halide sounds like halite, which is salt.  This is because halides are salt minerals and this class includes halite (table salt) & sylvite (alum) and fluorite.
Carbonates: Is a large group of minerals that contain (CO3)2 , also known as carbonate.  Minerals in this class include calcite, aragonite, rhodochrosite, smithsonite, and azurite & malachite.
Nitrates: Are minerals that have (NO3) in their formula and include nitratite & niter.
Borates:Are minerals that contain “BO3” in their formula and include borax and ulexite.
Phosphates: Are minerals that contain (AsO4) at the end of the formula.  Apatite, turquoise, variscite, wavellite, autunite, and vanadinite all belong to this class.
Sulfates: Are minerals that contain (SO4) in their formula.  And include minerals like barite, gypsum, celestine, anglesite, and crocoite.
Tungstates: Are minerals that contain W (tungsten) at the end of the formula.  It includes minerals like wolframite, scheelite, & wulfenite.
Silicates: This class is composed of 25% of the mineral kingdom and 80 of the most common 200 minerals are in this group.  It is defined as having the (SiO2) molecule at the end of the formula.  Some of the more common silicates include; garnets, quartz, topaz, kyanite, staurolite, the beryl family (aquamarine, emeralds, goshenite, heliodore, red beryl, morganite), tourmalines, jade, kunzite, mica, talc, the feldspar family (albite, labradorite, etc), sodalite, and the zeolite family (stilbite, heulandite, scolecite).

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