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Fluorite
A halide mineral with calcium fluoride, and trace amounts of yttrium and cerium. Cleaves perfectly in four directions, forming a octahedron. Harder than calcite, but softer than quartz. Comes in a range of colors: violet, blue, green, yellow, brown, and bluish black.
Garnet
As a group, garnets possess high indices of refraction, are relatively hard, have pretty colors, are wonderfully transparent, lack cleavage. are durable and make good candidates for gemstones. The raspberry and brown varieties are most commonly valued for their color and clarity.
Iolite
A fine violet gemstone, iolite is common name for cordierite, named after a French geologist P. L. A. Cordier. It is dichroic - its hue appears to change depending on the angle from which it is viewed.
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