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Made Famous by Rubies and Sapphires
Most people are familiar with corundum; however, very few people know it by its mineral name – instead they know it by the names “ruby” and “sapphire.” A gemstone-quality specimen of corundum with a deep red color is known as a “ruby.” A gemstone-quality corundum with a blue color is called a “sapphire.” Colorless corundum is known…
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Uses of Silver in Photography
Photography had been one of the primary industrial uses of silver until the recent rise of digital media. Traditional film photography relies on the light sensitivity of silver halide crystals present in film. When the film is exposed to light, the silver halide crystals change to record a latent image that can be developed into…
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What is Corundum?
Corundum is a rock-forming mineral that is found in igneous, metamorphic, and sedimentary rocks. It is an aluminum oxide with a chemical composition of Al2O3 and a member of the trigonal crystal system. The mineral is widely known for its extreme hardness and for the fact that it is sometimes found as beautiful transparent crystals in many different colors. The extreme hardness makes corundum an excellent abrasive,…
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Uses of Silver in Jewelry and Silverware
Jewelry and silverware are two other traditional uses of silver. Malleability, reflectivity, and luster make silver a beautiful choice. Because it is so soft, silver must be alloyed with base metals, like copper, as in the case of sterling silver (92.5% silver, 7.5% copper). Even though it resists oxidation and corrosion, silver can tarnish, but…
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Uses of Silver in Coins and Investments
Silver has traditionally served, with gold, as the metal used in coins. As a precious metal, silver is rare and valuable, making it a convenient store of wealth. In the past, people accumulated their wealth in the form of silver coins; today, they invest in investment-grade silver bullion. The fact that silver does not corrode…
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Uses of Charoite
Rocks containing abundant charoite with a pleasing color and interesting pattern are often cut into gems or used as an ornamental stone. Charoite cabochons, beads, tumbled stones and other items made of high-quality material can sell for high prices. Charoite is also used to make small sculptures and small utilitarian items that include vases, spheres, goblets, desk…
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Charoitite
Charoite is only known from rocks that are either charoite-rich or charoite-dominated. The name used for these rocks is “charoitite”. [5] Most people in the gem and lapidary trades simply refer to them as “charoite” and may not suspect that they are a rock which contains a variety of rare minerals. Charoitite is a contact…
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Uses of Silver in Chemical Production
Silver acts as a catalyst to produce two important chemicals: ethylene oxide and formaldehyde. Ethylene oxide is used to produce molded plastics, such as plastic handles, and flexible plastics, such as polyester. It is also a major ingredient in antifreeze. Formaldehyde is used to make solid plastics and resins and as a protective coating. It…
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Charoite’s Chemical Composition
Charoite is a complex silicate mineral. Published chemical compositions are in disagreement. We checked numerous references, and each one presented a different composition. The compositions reported below are from the Glossary of Geology [3], Mineralogical Magazine [4], and Mindat.org [1].(K,Na)5(Ca,Ba,Sr)8Si8O46(OH,F)·nH2O [3](K,Sr,Ba,Mn)15-16(Ca,Na)32[Si70(O,OH)180] (OH,F)4·nH2O [4](K,Sr)15-16(Ca,Na)32[Si6O11(O,OH)6]2 [Si12O18(O,OH)12]2[Si17O25(O,OH)18]2 (OH,F)4·~3H2O [1] Determining a composition for this mineral might be difficult for two reasons: 1) well-formed…
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Uses of Silver in Brazing and Soldering
Brazing and soldering make use of silver’s high tensile strength and ductility to create joints between two metal pieces. Brazing takes place at temperatures above 600°C, while soldering takes place at temperatures below 600°C. Silver scrap can be used in brazing and soldering because these processes do not require very pure silver. Brazing and soldering…