The value of a diamond as a gemstone is based on the "four Cs: color, clarity, cut and carat(weight). Only 20% of all diamonds are suitable for gemstones, the rest being used in industry as an abrasive for drillings, boring or grinding. The diamond's most distinctive features ate its hardness and sparkle, which are unmatched by any other crystal.
Crystal structure: isometric
Color: Colorless, yellow tones, blue, brown-green, red, violet.