Gems are characterized in terms of refractive index, dispersion, specific gravity, hardness, cleavage, fracture and luster. They may exhibit pleochroism or double refraction. They may have luminescence and a distinctive absorption spectrum. a b c Scheel, Hans J (April 1, 2000). "Historical aspects of crystal growth technology". Journal of Crystal Growth. 211 (1): 1–12. Bibcode: 2000JCrGr.211....1S. doi: 10.1016/S0022-0248(99)00780-0. ISSN 0022-0248. Archived from the original on April 15, 2023 . Retrieved April 15, 2023.

List of gemstones by species - Wikipedia List of gemstones by species - Wikipedia

Padparadscha Sapphires: 10 Tips On Judging The Rare Gem". The Natural Sapphire Company Blog. April 6, 2015. Archived from the original on January 19, 2018 . Retrieved January 19, 2018. Nassau, Kurt (1990). "Synthetic Gem Materials in the 1980s" (PDF). Gems & Gemology. 26 (1): 50–63. doi: 10.5741/GEMS.26.1.50. Archived (PDF) from the original on November 1, 2021 . Retrieved April 15, 2023.

Another important new gemstone that has been rising in popularity is Cuprian Elbaite Tourmaline which are also called "Paraiba Tourmaline". Paraiba tourmaline were first discovered in early 1990 and recently in 2007 in Mozambique, Africa. [23] They are famous for their Glowing Neon Blue Color. Paraiba Tourmaline have become one of the most popular gemstones in recent times thanks to their unique color and recently considered to be one of the important gemstones after Ruby, Emerald and Sapphire according to Gübelin Gemlab. Even though it is a tourmaline, paraiba are considered to be one of the most expensive gemstones. Emeralds containing natural fissures are sometimes filled with wax or oil to disguise them. This wax or oil is also colored to make the emerald appear of better color as well as clarity. Turquoise is also commonly treated in a similar manner.

Gemstones of the World - Walter Schumann - Google Books Gemstones of the World - Walter Schumann - Google Books

Apart from jewelry, from earliest antiquity engraved gems and hardstone carvings, such as cups, were major luxury art forms. A gem expert is a gemologist, a gem maker is called a lapidarist or gemcutter; a diamond cutter is called a diamantaire. Poudretteite was discovered in 1965 at the Poudrette Quarry in Canada and named after the quarry's owners and operators, the Poudrette family. Bleaching [ edit ] Pearls are a gemstone that is commonly treated with hydrogen peroxide to remove unwanted coloursa b c d e Weldon, R. "An Introduction to Synthetic Gem Materials" (PDF). Archived (PDF) from the original on April 15, 2023 . Retrieved April 14, 2023. Cultured, synthetic, or "lab-created" gemstones are not imitations: The bulk mineral and trace coloring elements are the same in both. For example, diamonds, rubies, sapphires, and emeralds have been manufactured in labs that possess chemical and physical characteristics identical to the naturally occurring variety. Synthetic (lab created) corundum, including ruby and sapphire, is very common and costs much less than the natural stones. Small synthetic diamonds have been manufactured in large quantities as industrial abrasives, although larger gem-quality synthetic diamonds are becoming available in multiple carats. [37] A few gemstones are used as gems in the crystal or other forms in which they are found. Most, however, are cut and polished for usage as jewelry. The two main classifications are stones cut as smooth, dome-shaped stones called cabochons, and stones which are cut with a faceting machine by polishing small flat windows called facets at regular intervals at exact angles. The flame fusion process is completed in a Verneuil furnace. The furnace consists of an inverted blowpipe burner which produces an extremely hot oxyhydrogen flame, a powder dispenser, and a ceramic pedestal. [44] A chemical powder which corresponds to the desired gemstone is passed through this flames. This melts the ingredients which drop on to a plate and solidify into a crystal called a Boule. [44] For corundum the flame must be 2000°C. This process takes hours and yields a crystal with the same properties as its natural counterpart.

Gemstones of the World - Fifth Edition - Rock tumbler Gemstones of the World - Fifth Edition - Rock tumbler

Flame fusion process was the first process used which successfully created large quantities of synthetic gemstones to be sold on the market. [43] This remains the most cost effective and common method of creating corundums today. Virtually all blue topaz, both the lighter and the darker blue shades such as "London" blue, has been irradiated to change the color from white to blue. Most green quartz (Oro Verde) are also irradiated to achieve the yellow-green color. Diamonds are mainly irradiated to become blue-green or green, although other colors are possible. When light-to-medium-yellow diamonds are treated with gamma rays they may become green; with a high-energy electron beam, blue. [35] Waxing/oiling [ edit ] New process promises bigger, better diamond crystals". Carnegie Institution for Science. Archived from the original on December 1, 2010 . Retrieved January 7, 2011. To produce corundum, a pure aluminium powder is used with different additives to achieve different colors. [44]

Prior to development of synthesising processes the alternatives on the market to natural gemstones were imitations or fake. It was in 1837 that the first successful synthesis of ruby occurred. [43] French chemist Marc Gaudin managed to produce small crystals of ruby from melting together potassium aluminium sulphate and potassium chromate through what would later be known as the flux melt process. [44] Following this, another French chemist Fremy was able to grow large quantities of small ruby crystals using a lead flux. [45] Today the gemstone trade no longer makes such a distinction. [15] Many gemstones are used in even the most expensive jewelry, depending on the brand-name of the designer, fashion trends, market supply, treatments, etc. Nevertheless, diamonds, rubies, sapphires, and emeralds still have a reputation that exceeds those of other gemstones. [16] Belley, Phillippe (2021). "Coloured gemstones: uncharted waters in economic geology". Atlantic Geology. 57: 139. Grandidierite was discovered by Antoine François Alfred Lacroix (1863–1948) in 1902 in Tuléar Province, Madagascar. It was named in honor of the French naturalist and explorer Alfred Grandidier (1836–1912).

List of individual gemstones - Wikipedia List of individual gemstones - Wikipedia

Flux growth process was the first process which was able to synthesize emerald. [41] Flux growth begins with a crucible which can withstand high heat; either graphite or platinum which is filled with a molten liquid referred to as flux. [45] The specific gem ingredients are added and dissolved in this fluid and recrystallize to form the desired gemstone.This is a longer process compared to the flame fusion process and can take two months up to a year depending on the desired final size. [46] Hydrothermal Growth (Solution Process) [ edit ] Katz, Michael (2005). Gemstone Energy Medicine: Healing Body, Mind and Spirit. Natural Healing Press. ISBN 9780924700248 . Retrieved April 6, 2020. Gemstones are often treated to enhance the color or clarity of the stone. In some cases, the treatment applied to the gemstone can also increase its durability. Even though natural gemstones can be transformed using the traditional method of cutting and polishing, other treatment options allow the stone's appearance to be enhanced. [27] Depending on the type and extent of treatment, they can affect the value of the stone. Some treatments are used widely because the resulting gem is stable, while others are not accepted most commonly because the gem color is unstable and may revert to the original tone. [28] Early history [ edit ] Geographic Origin Determination of Paraíba Tourmaline". Archived from the original on April 9, 2022 . Retrieved March 17, 2022. Colors [ edit ] Nearly 300 variations of diamond color exhibited at the Aurora display at the Natural History Museum in London A variety of semiprecious stones in a piece of jewellery

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urn:lcp:gemstonesofworld0000schu_b3o8:epub:899cfe24-e02a-4f80-aa7a-44aeec62e69d Foldoutcount 0 Identifier gemstonesofworld0000schu_b3o8 Identifier-ark ark:/13960/s2pww0z5kr1 Invoice 1652 Isbn 0806930888 Lccn 77079503 //r83 Ocr tesseract 5.0.0-1-g862e Ocr_detected_lang en Ocr_detected_lang_conf 1.0000 Ocr_detected_script Latin Ocr_detected_script_conf 0.9757 Ocr_module_version 0.0.14 Ocr_parameters -l eng+deu Old_pallet IA14624 Openlibrary_edition In modern times gemstones are identified by gemologists, who describe gems and their characteristics using technical terminology specific to the field of gemology. The first characteristic a gemologist uses to identify a gemstone is its chemical composition. For example, diamonds are made of carbon ( C) and rubies of aluminium oxide ( Al Found all over the world, the industry of coloured gemstones (this meaning anything other than diamonds) is currently estimated to be around 10–12 billion US dollars. [4] Hervey, P. R.; Foise, J. W. (February 1, 2001). "Synthetic quartz crystal — A review". Mining, Metallurgy & Exploration. 18 (1): 1–4. doi: 10.1007/BF03402862. ISSN 2524-3470. S2CID 140031745. Artificial treatment of gemstones". Dictionary of Gems and Gemology. Berlin, Heidelberg: Springer Berlin Heidelberg. 2009. pp. 50. doi: 10.1007/978-3-540-72816-0_1308. ISBN 9783540727958.