Also as barrel-shaped hexagonal crystals, modified octahedrons, massive, and as rounded, waterworn alluvial pebbles. Crystals are commonly smooth or rounded on the edges due to alluvial action. Crystals are usually elongated and striated crosswise, and sometimes occur in thin plates. Occasionally also multicolored or striped.Ĭrystals occur as hexagonally shaped prismatic and tabular crystals, and as bipyramidal hexagons that are wider in the center and taper thinly on the ends. Many colors, including blue, red, violet, pink, green, yellow, orange, gray, white, colorless, and black. Some dark blue stones from certain localities may also be made a bright blue desirable color. Natural Ruby and Sapphire gemstones may have their color artificially enhanced or deepened through heat treatment when used as gems. This process is called the Verneuil process. Synthetic gems are also easily created by adding traces of certain color producing elements to the Corundum solution, and letting the solution solidify into a boule, or synthetic, unprocessed "mineral" with a particular shape. Erosion may cause Emery to crumble and form sand, which are sometimes called "black sands."Ĭorundum is easily synthesized, and many Corundum abrasives are synthetic. The industrial term "emery" describing Corundum abrasives is derived from the variety Emery which is mined specifically for its use as an abrasive.
These are fairly common forms, and due to their great hardness and prevalence are the most favorable abrasives. Translucent brown Corundum and Emery are the most common forms of Corundum. It is also unaffected by acids and most environments. For all practical purposes, it is the hardest mineral after Diamond, making it the second hardest mineral.
Sapphire is also only used to describe the gem variety otherwise it is simply called Corundum.Ĭorundum is a very hard, tough, and stable mineral. Ruby is the red variety, and Sapphire is the variety that encompasses all other colors, although the most popular and valued color of Sapphire is blue. Ruby and Sapphire are scientifically the same mineral, but just differ in color. Corundum is best known for its gem varieties, Ruby and Sapphire.
0 kommentar(er)
