dentifying the minerals you find is softer than 3; a knife blade will scratch Color pretty much like solving a mystery anything less than 5 ½; and a steel file A mineral may have a distinctive color, I and can be just as much fun. It can will scratch anything under 6 ½. but can also cause some confusion. The also be frustrating. The first, and Anything harder than 5 ½ will scratch color of a sample may be the property biggest clue you have is where you glass. of a pure mineral or a result of found it. Always make a note of the impurities within it. An additional location when you collect your Cleavage investigation of color would include a samples, so you don’t mix them Cleavage is the way that a mineral will streak test, where the color of the fine up later. Regional mineral split or break along a flat surface. It powder left behind when a mineral is guides can tell you where to is different from the shape of the scraped across and unglazed tile. look and will usually list the crystal, though both are minerals found in each area. Start actually determined by crystal Specific Gravity / Density with those and try to narrow down the structure. Cleavage is Simply holding a dense mineral in one possibilities by using some of the classified by the quality of hand while holding a far less dense following tests. A mineral field guide surface produced as well as sample of the same dimension in the should tell you each of the following ease with which it breaks. other hand quickly demonstrates that properties for the minerals Not all minerals will minerals have different densities or listed in it . produce regular surfaces mass per unit volume. Most are too when broken. close to measure with the hands or even Hardness less sophisticated lab equipment. The The hardness of a mineral Fracture specific gravity of a mineral is the depends on the strength of its Those minerals which standard measure. The number chemical bonds. It do not break along represents the weight of the mineral in may vary if your regular surfaces air divided by the weight of an equal sample is weak for may be identified by volume of pure water at 4°C. one reason or another, their fracture rather than cleavage. but still, hardness is something easily Fractures may be in many shapes and Crystal Habit investigated. Check out the Moh’s appearances including conchoidal The way a particular mineral Scale of Relative Hardness in this (smooth curved surfaces), fibrous, or grow as crystals are usually brochure. Minerals are listed from the splintery. named after the geometric softest, #1 to the hardest, #10. You can shapes they resemble. Their figure out the hardness of a sample by Luster crystal habit is determined by trying to scratch it with known Luster is the way a surface of a mineral atomic structure and speed with minerals. Also, your fingernail will reflects light. It can be metallic, which they grow. scratch anything softer than 2 ½ on the vitreous, resinous, greasy, pearly, silky, scale; a penny will scratch anything or adamantine.
Moh’s Scale of Resources
Relative Hardness Chesterman, Charles W. The Audubon Society Field Guide to North American Rocks and Minerals. NY: Alfred A. Knopf, 1992. Let’s Explore Cvancara, Alan M. A Field Manual for the 1. Talc Amateur Geologist. NY: John Wiley and Sons, 1995. Geology & Mining Kittinger, Jo S. A Look at Minerals from 2. Gypsum Galena to Gold. NY: Franklin Watts, 1998. RQ educational series #2 Pough, Frederick H. Peterson Field Guide to Rocks and Minerals. Boston: Houghton 3. Calcite Mifflin Company, 1988.
Pough, Frederick H. Peterson First Guide to Rocks and Minerals. Boston: Houghton Mineral 4. Fluorite Mifflin Company, 1991. Identification
5. Apatite
6. Feldspar © 2002 Randy E Newcomer
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