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IGI provides independent grading reports, colored stone reports, identification and appraisal reports, diamond authentication and attestations of origin, and laser inscription services. They also offers diamond and colored stone courses through IGI's Schools of Gemology. [7] Graduates from the IGI school of Gemology are awarded an IGI Diploma.
A 2010 effort led by State Senator Gloria J. Romero, a Democrat from Los Angeles, sought to remove serpentine from its perch as the state's official stone. Organizations such as the Asbestos Disease Awareness Organization have supported the move as the olive green rock is a source of chrysotile , a form of asbestos that can cause mesothelioma ...
GIA colored stone identification reports may include a comment about any treatments detected and an opinion of country of origin for ruby, sapphire, emerald and tourmaline. Pearl reports specify the weight, size, shape, color, origin (natural or cultured) and presence of treatments.
Bannerstones are artifacts usually found in the Eastern United States that are characterized by a centered hole in a symmetrically shaped carved or ground stone. The holes are typically 1 ⁄ 4" to 3 ⁄ 4" in diameter and extend through a raised portion centered in the stone. They usually are bored all the way through but some have been found ...
The following is a list of rock types recognized by geologists.There is no agreed number of specific types of rock. Any unique combination of chemical composition, mineralogy, grain size, texture, or other distinguishing characteristics can describe a rock type.
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Jet is a type of lignite, [1] the lowest rank of coal, and is a gemstone.Unlike many gemstones, jet is not a mineral, but is rather a mineraloid. [2] It is derived from wood that has changed under extreme pressure.
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.