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Athabasca University

Rocks and Minerals - Identify a Mineral

Rocks and Minerals | Minerals | Identify a Mineral | Rocks | Credits

 

To identify a mineral from our database, select from one or more of the variables below and press search. The more variables selected increases the accuracy of your search.

Hardness1

Colour2

Streak3

Lustre4

1 The HARDNESS of a mineral refers to the relative ease with which the mineral can be scratched by another. The standard scale used for measuring hardness in geology in the Mohs’ hardness scale where 10 minerals are given hardness values of 1 to 10, 1 being the softest and 10 the hardest. The 10 minerals in  the Mohs’ hardness scale are talc(1), gypsum(2), calcite(3), fluorite(4), apatite(5), feldspar(6), quartz(7), topaz(8), corundum(9) and diamond(10).

2 COLOR refers to the natural color of the mineral. Though it is a very useful property in identification, it is seldom used as the sole parameter in identifying minerals. This is because color can be very variable in minerals. Hence, it should be used with caution.

3 STREAK is the color that a mineral displays when pulverized into a fine powder. Typically, to perform such a test, the mineral sample is scraped across a porcelain plate to give a streak with a characteristic colour. It is important to note that a porcelain plate will only work with those minerals that are softer than porcelain. Minerals that are harder than porcelain would require a harder surface.

4 LUSTRE refers to the intensity and quality of light reflected from a mineral’s surface. Usually, luster is described by comparing it to surfaces of common substances.

 

Updated February 26 2015 by Student & Academic Services

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