Another significant Burmese deposit is Mong Hsu, which is currently a major Ruby producer, though its color isn’t as fine as the Mogok material. Notable Localities: The area of Mogok, Myanmar (Burma) is the source of some of the best gem-quality Ruby. Luster can be pearly, vitreous, or adamantine.Ĭorundum occurs in silica-poor rocks including altered metamorphic rocks such as marble and hornfels, in nepheline syenite pegmatites, and in placer deposits. Corundum may fluoresce red, yellow, or orange under short-wave UV light. Rubies may fluoresce red under long-wave ultraviolet light. Natural Ruby and Sapphire gemstones may have their color artificially enhanced or deepened through heat treatment when used as gems. Synthetic gems are also easily created by adding traces of certain color-producing elements to the Corundum solution. Other habits include barrel-shaped hexagonal crystals, modified octahedrons, rhombohedral crystals, massive or granular.Ĭorundum is easily synthesized, and many Corundum abrasives are synthetic. Crystals are usually elongated and striated crosswise. Crystals occur as hexagonally shaped prismatic and tabular crystals, and as bipyramidal hexagons that are wider in the center and taper thinly on the ends. Emory is mined for use as an abrasive on sandpaper and on large tools used to machine metals.Ĭorundum belongs to the Trigonal Crystal System in the class of Hexagonal scalenohedral. Saving Earth Britannica Presents Earth’s To-Do List for the 21st Century.Corundum is the second hardest mineral on earth (after diamond).Britannica Beyond We’ve created a new place where questions are at the center of learning.100 Women Britannica celebrates the centennial of the Nineteenth Amendment, highlighting suffragists and history-making politicians.COVID-19 Portal While this global health crisis continues to evolve, it can be useful to look to past pandemics to better understand how to respond today.Student Portal Britannica is the ultimate student resource for key school subjects like history, government, literature, and more.This Time in History In these videos, find out what happened this month (or any month!) in history.
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