3.7| Mineral Groups Reading and Exercise

Background 

"We classify minerals according to the anion part of the mineral formula, and mineral formulas are always written with the anion part on the right. For example, for pyrite (FeS₂), Fe2+ is the cation, and S– is the anion. This helps us to know that it’s a sulfide, but it is not always that obvious. Hematite (Fe₂O₃) is an oxide; that’s easy, but anhydrite (CaSO₄) is a sulfate because SO₄– is the anion, not O. Along the same lines, calcite (CaCO₃) is a carbonate, and olivine (Mg₂SiO₄) is a silicate. Minerals with only one element (such as S) are native minerals, while those with an anion from the halogen column of the periodic table (Cl, F, Br, etc.) are halides." The passage was taken from Physical Geology by Earle, S.  Visit the Mineral Groups page from Physical Geology for additional background information to help you complete this exercise.  You have 3 attempts and no time limit.