How to Identify Common Minerals
The first principle for identifying common minerals is, "Rocks and minerals are not the same thing." Every rock contains two or more different minerals, and the various mineral combinations are what make each type of rock unique. There are thousands of known minerals, yet only about 100 of these are common enough to make up the main components of rocks. Use the following steps to help you identify common minerals.
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Things You'll Need
- Field guide
- Magnifying glass
- Unglazed porcelain tile
- Hammer
- Copper penny
- Glass plate
- Magnet
- Diluted hydrochloric acid
Instructions
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Get a good mineralogy field guide. This will allow you to read about each of the common minerals, see what they look like and compare the physical properties of the specimens you find to the photos in your guide.
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Do some preliminary reading before going out to hunt for minerals to identify. This will give you an opportunity to learn common mineral-identification terminology, as well as the actual physical characteristics that differentiate minerals from one another. You'll learn that such things as color, streak, transparency, luster, hardness, cleavage and fracture, along with other factors like specific gravity and crystal form, determine the nature of common minerals.
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Memorize the above properties which are used to identify the common minerals. Learn the meaning of each term. This will make your job easier when you're out in the field.
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Go out and collect as many interesting-looking specimens as you'd like to try to identify.
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Use your field guide to help you determine which specimens to collect for further study. Comparing them to the pictures in the guide will give you a better idea of which types of minerals the rocks you find are likely to contain--or at least which minerals they visually resemble.
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Study your specimens further at home. Use the items in the above list as instructed in your guide to check the properties of each specimen against the measurements that indicate the different types of common minerals. Use the porcelain tile to test streak, the hammer to test cleavage or fracture, the penny and glass plate to estimate hardness, the magnet to identify metallic minerals and the diluted hydrochloric acid to test powdered minerals. Follow guide instructions carefully, taking notes to help you reach an accurate conclusion.
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Tips & Warnings
Never test good mineral samples or items of value, such as jewelry, with any of the methods that cause damage to the sample.
Never taste a mineral unless specifically instructed to do so by an expert.
Use dilute hydrochloric acid with care.
