The qualities of gemstone beads are beauty, rarity and durability. The beauty of a gem depends on its properties that how it looks or visible, its features include shine, fire and color of a gemstone bead. The durability of the gemstone beads depend on hardness and resistance to cleavage or breakage. If we look at the physical properties of gems, some resembles each other and some are quite different.
These can be recognized by it crystal properties, index of refraction of light, hardness, presence or absence of cleavage, type of fracture (concordat, even, or uneven) in stones without cleavage, specific gravity, color, streak (color of the powder as determined by rubbing it over white, unglazed porcelain), luster (appearance of the surface in reflected light – adamantine, vitreous, resinous, greasy, silky, or pearly), and transparency. Minor properties that serve to identify some stones are chiromancy (changeable luster or color under undulating light), opalescence, asterism (star like sparkling), and play of color, fluorescence, phosphorescence, iridescence, and electrical properties.
The unit of weight used for gemstones is the metric carat; one carat equals 200 mg.
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