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A gemstone (also called a fine gem, jewel, precious stone, semiprecious stone, or simply gem) is a piece of mineral crystal which, when cut or polished, is used to make jewelry or other adornments.
Sapphire (gem corundum of any color except red, especially blue varieties) Sard (a variety of chalcedony/quartz) Satinspar (a variety of gypsum) Selenite (a variety of gypsum) Simetite (a variety of amber) Smoky quartz (a brown or black variety of quartz) Soda niter (synonym of nitratine) Spectrolite (a variety of labradorite) Spessartite ...
Calcite. Manganoan calcite (var.); Caledonite; Canasite; Cancrinite. Vishnevite; Carletonite; Carnallite; Cassiterite; Catapleiite; Cavansite; Celestite; Ceruleite ...
Ruby is one of the most popular traditional jewelry gems and is very durable. Other varieties of gem-quality corundum are called sapphires. Ruby is one of the traditional cardinal gems, alongside amethyst, sapphire, emerald, and diamond. [3] The word ruby comes from ruber, Latin for red. The color of a ruby is due to the element chromium.
The powdered gem mineral is then melted (or a metallic mixture directly burned in an oxygen flame) the residue of which then drips through a furnace onto a boule. The boule where the corundum or spinel cools down and crystallizes, spins and thus causes the curved striations, which are diagnostic for a lab-created gem: Natural corundum does not ...
Originating from the Persian word for the gem, lāžward, [1] lapis lazuli is a rock composed primarily of the minerals lazurite, pyrite and calcite. As early as the 7th millennium BC, lapis lazuli was mined in the Sar-i Sang mines, [2] in Shortugai, and in other mines in Badakhshan province in modern northeast Afghanistan. [3]
A large trade in gem-grade diamonds exists. Although most gem-grade diamonds are sold newly polished, there is a well-established market for resale of polished diamonds (e.g. pawnbroking, auctions, second-hand jewelry stores, diamantaires, bourses, etc.).
The most suitable setting for gem amethyst is a prong or a bezel setting. The channel method must be used with caution. [42] 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.