Frequently Asked Questions (FAQ) / Color - Streak for Gemstones

What is "color of streak"? Is it important?

The streak test is one of the many methods used to identify gemstones. Each gemstone has an inherent color, that is, it's true color not affected by any impurities. The color of a mineral when powdered is called the streak of the mineral. Crushing and powdering a mineral eliminates some of the effects of impurities and structural flaws, and is therefore more diagnostic for some minerals than their color. Streak can be determined for any mineral by crushing it with a hammer, but it is more commonly obtained by rubbing the mineral across the surface of a hard, unglazed porcelain material called a streak plate. The color of the powder left behind on the streak plate is the mineral's streak.

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