Last month we learned why crystals grow in geometric patterns, and listed some definitions of terms used in mineralogy.  Common chemical compounds or elements classify minerals.  They are: 

1)      Native Elements, which include metals, semi-metals, and non-metals of mainly one atom type, like gold (Au), sulfur (S), and graphite (C); 

2)      Sulfides (S), which are mainly metals and semi-metals with a sulfur ion, like pyrite (FeS), chalcopyrite (CuFeS₂), and galena (PbS)); 

3)      Oxides and Hydroxides, which contain the oxygen atom (O) or the hydroxl (OH) ion, like cuprite (Cu₂O), and goethite (ά FeO^.OH);

Crystal structure of an oxide, ZnO
 (Zinc Oxide)

4)      Halides, which include a metal and the halogen elements fluorine (F), chlorine (Cl), bromide (Br), and iodine (I), like fluorite (CaF₂), and halite (NaCl); 

5)      Nitrates (NO₃), Carbonates (CO₃), and Borates (BO₃), like calcite (CaCO₃), dolomite (CaMg(C CO₃)(OH)), azurite (Cu₃(CO₃)₂(OH)), malachite (Cu₂(CO₃)(OH)₂), borax (Na₂B₄O₇^.10H₂O), and ulexite (NaCaB₅O₉^.8H₂O); 

6)      Sulfates (SO₄), Chromates (CrO₄), Molybdates (MoO₄), and Tungstates (WO₄), like gypsum (CaSO₄^.2H₂O), crocoite (PbCrO₄), wulfenite (PbMoO₄), and scheelite (CAWO₄); 

7)      Phosphates (PO₄), Arsenates (AsO₄), and Vanadates (VO₄), which include monazite ((Ce, La, Nd, Th)PO₄), adamite (Zn₂(As O₄)), and conichalcite.(CaCu(AsO₄)(OH)); 

8)      Silicates (SiO₂), like quartz (SiO₂), opal (SiO₂^.nH₂O), phenakite (Be₂ SiO₄), grossular garnet (Ca₃Al₂(SiO₄)₃), and clinochlore ((Mg,Fe⁺²)₅Al(Si, Al)₄O₁₀(OH)₈); and  

9)      Organic Substances, like whewellite (CaC₂O₄^.H₂O), which crystallizes from coal, and amber (amorphous fossilized resin). 

Thanks again to my professors at the University of Nebraska at Omaha, my college mineralogy text (Manual of Mineralogy, Klein and Hurlbut, 20th Edition); Simon & Schuster's Guide to Rocks and Minerals; Dictionary of Geological Terms, 3rd Edition, Bates and Jackson, AGI; Mineralogy, Sinkankas; and my college chemistry text (Chemistry, the Central Science, 4th Edition, Brown & LeMay) for providing the basis for this article.   

Continuation of this Series of Articles:
The Mighty Atom, Part Four
The Mighty Atom, Part Five