Diamond is one of the best-known and most sought-after gemstones. The hardness of diamond and its high dispersion of light once faceted—giving the diamond its characteristic "fire"—make it useful and desirable as jewellery, currency, and as other decorative items. While the finest quality diamonds are totally colourless and clear, lower quality diamonds have traces of various colours, such as, yellows, pinks, greens, and blacks.12
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- Diamond (real-world gemstone) on Wikipedia