安裝中文字典英文字典辭典工具!
安裝中文字典英文字典辭典工具!
|
- Corundum - Wikipedia
Corundum is a crystalline form of aluminium oxide (Al2O3) typically containing traces of iron, titanium, vanadium, and chromium [3][4] It is a rock -forming mineral It is a naturally transparent material, but can have different colors depending on the presence of transition metal impurities in its crystalline structure [7]
- Corundum: Use as a Gemstone, Abrasive, Refractory - Geology. com
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 Al 2 O 3 and a member of the trigonal crystal system
- Corundum | Properties, Formation, Uses » Geology Science
Corundum is a mineral that is primarily composed of aluminum oxide (Al2O3) and is one of the naturally occurring crystalline forms of aluminum oxide It is a very hard mineral and is commonly used as an abrasive in various industrial applications
- Corundum | Aluminum Oxide, Gemstone, Abrasive | Britannica
corundum, naturally occurring aluminum oxide mineral (Al 2 O 3) that is, after diamond, the hardest known natural substance Its finer varieties are the gemstones sapphire and ruby (qq v ), and its mixtures with iron oxides and other minerals are called emery (q v )
- Corundum Value, Price, and Jewelry Information - International Gem Society
Corundum is very compact, dense, and lacks gemstone cleavage It’s also the second hardest natural mineral after diamond Gem-quality corundum is also quite rare These factors make both varieties of corundum some of the most highly desired jewelry stones Ruby is the red variety of corundum
- Corundum: Mineral information, data and localities. - mindat. org
A red, gem variety of corundum The red colour is caused by minor amounts of trivalent Cr replacing Al in the crystal structure In traditional gemmological terms, ruby has to be blood-red and of clear, facetable quality to justify the name
- The Mineral corundum - The Mineral and Gemstone Kingdom
Corundum is a very hard, tough, and stable mineral For all practical purposes, it is the hardest mineral after Diamond, making it the second hardest mineral It is also unaffected by acids and most environments Translucent brown Corundum and Emery are the most common forms of Corundum
- Corundum Gem Guide and Properties Chart - Gemstones. com
Corundum is a mineral species best known for its two popular gemstone varieties, sapphire and ruby All colors of corundum except red are known as sapphire The term sapphire, when used without any modifiers, refers to only the blue variety of corundum
|
|
|