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How to Streak a Mineral

Ever wonder how to tell the difference between fool's gold (pyrite) and real gold? One way is to crush some of the sample into powder. Often the color of the powder is different from the color of the mineral itself. An alternative is to do a streak test. Rather than pulverizing the entire sample, you turn a small portion into powder with the help of a streak plate. Streak plates are unglazed porcelain, preferably white.

Things You'll Need

Towel
Unglazed white porcelain

Instructions

- 1
  Clean with water and dry both the streak plate and the mineral you're going to test. This will prevent contaminating the streak result.
- 2
  Drag a pointed edge of the mineral across the streak plate, applying light pressure. To avoid damaging the mineral, push against the plate just hard enough to create a streak of mineral powder.
- 3
  Compare the color of the streak to a list, database or chart of mineral streak colors. Consider the streak color as well as other identifying characteristics, such as hardness and density, to identify the mineral.

Rocks & Minerals