What Tests Do Scientists Use to Identify Minerals?

For a geologist, identifying an unknown mineral begins with simply looking at it. The way a mineral looks reveals much about its texture, composition and history. Minerals can be classed according to their luster. They can be classed as metallic, glassy or dull, with certain intermediate classifications such as waxy or adamantine.

Another clue that can be found with a visual examination comes from the mineral's color. Lazurite, for example, tends to be blue, while pyrite is typically yellowish. Some minerals have a characteristic color, such as quartz, which is usually white or clear, but can be many other colors as well.

Another test minerologists perform is to check the hardness of the sample. Hardness is measured on the 10-point Mohs scale. On this scale, a fingernail is a 2, a coin is a 3, and a metal knife or iron nail tends to rate 5.5. Harder substances, those with higher ratings, are able to scratch softer elements.

Still another test that is available to scientists is a magnetic evaluation. Some minerals are magnetic, and the field they generate can be detected by a powerful magnet held near the sample. It is also possible to detect the presence of a magnetic field simply by holding the sample close to a compass.