3.8| Mineral Groups Reading and Exercise

Introduction

"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. 

The most common mineral group is the silicates, which can be identified by mineral formulas that contain SiO written together. For example, olivine (Mg₂SiO₄), quartz, (SiO₂), and biotite [K(Mg, Fe)₃AlSi₃O₁₀(F, OH)₂] are all silicates. 

Visit the Mineral Groups page from Physical Geology. This will provide you with the background information needed to complete this exercise. You have 3 attempts and no time limit.  

Directions

Please read the introductory background information above, including the section from your textbook, then answer the questions below.  

Learning Objectives

Course SLO

• Students can use physical properties to identify minerals and can explain mineral-forming processes

Learning Outcomes

• Describe the importance of chemical bonding as it relates to forming minerals
• Use diagnostic physical properties of minerals, i.e., hardness, cleavage, streak, heft, etc., to identify common rock-forming minerals 
• Use chemical formulas to classify minerals into mineral groups
• Identify the minerals most commonly found in rocks