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Gemstone. Group of precious and semiprecious stones—both uncut and faceted—including ( clockwise from top left) diamond, uncut synthetic sapphire, ruby, uncut emerald, and amethyst crystal cluster. A gemstone (also called a fine gem, jewel, precious stone, semiprecious stone, or simply gem) is a piece of mineral crystal which, in cut and ...
Community portal; Recent changes; Upload file; ... Chatoyant gems. Some minerals made into gemstones may display a chatoyancy or cat's eye effect, these include:
Emerald. Emerald is a gemstone and a variety of the mineral beryl (Be 3 Al 2 (SiO 3) 6) colored green by trace amounts of chromium or sometimes vanadium. [2] Beryl has a hardness of 7.5–8 on the Mohs scale. [2]
Sapphires. The Logan Sapphire. The Star of Bombay, given to Mary Pickford by Douglas Fairbanks, Sr. The Star of India. The Stuart Sapphire. The Black Star of Queensland. The Star of Adam, with a weight of 1,404.49 carats (280.898 g) The largest star sapphire in the world. The Queen Marie of Romania Sapphire.
The most suitable setting for gem amethyst is a prong or a bezel setting. The channel method must be used with caution. Amethyst has a good hardness, and handling it with proper care will prevent any damage to the stone. Amethyst is sensitive to strong heat and may lose or change its colour when exposed to prolonged heat or light.
Website. www .gia .edu. The Gemological Institute of America ( GIA) is a nonprofit institute based in Carlsbad, California. It is dedicated to research and education in the field of gemology and the jewelry arts. [1] Founded in 1931, GIA's mission is to protect buyers and sellers of gemstones by setting and maintaining the standards used to ...
Diamond cutting is the art and science of creating a gem-quality diamond out of mined rough. The cut of a diamond describes the manner in which a diamond has been shaped and polished from its beginning form as a rough stone to its final gem proportions. The cut of a diamond describes the quality of workmanship and the angles to which a diamond ...
Main diamond producing countries. Diamond is a solid form of the element carbon with its atoms arranged in a crystal structure called diamond cubic.Another solid form of carbon known as graphite is the chemically stable form of carbon at room temperature and pressure, but diamond is metastable and converts to it at a negligible rate under those conditions.