It is a black granular form of corundum, in which the mineral is intimately mixed with magnetite, hematite, or hercynite. [6] In addition to its hardness, corundum has a density of 4.02 g/cm 3 (251 lb/cu ft), which is unusually high for a transparent mineral composed of the low-atomic mass elements aluminium and oxygen. [10]

2024年7月1日 · Black Corundum: Black corundum is a type of corundum that is black or dark gray in appearance. It is typically used as an abrasive, as well as for refractory applications due to its high thermal conductivity and chemical resistance.

2024年11月26日 · Black Corundum is a dark, opaque variety of corundum, a crystalline form of aluminum oxide (Al₂O₃). It is known for its toughness and durability, making it valuable for both industrial and ornamental purposes.

2014年9月22日 · The largest documented single natural crystal of corundum ever found measures about 65×40×40 cm (26×16×16 in), and weighs 152 kg (335 lb). Corundum can not only be artificially synthesized, but even natural gem stones are …

Black Corundum, also known as Black Sapphire or Black Ruby, forms within metamorphic rocks, where intense pressure and temperature create the perfect conditions for its existence. Its distinctive color arises from trace elements like iron and titanium, imparting the gem with its …

- Black, massive variety of Corundum, with color caused by mixture of Magnetite, Hematite, and Spinel. - Orange-pink gem variety of Sapphire. Padparadschah is a very rare and sought after variety. - Pink to red variety of Corundum. See the gemstone section …

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 …

Check out our black corundum selection for the very best in unique or custom, handmade pieces from our gemstones shops.

This Corundum gemstone guide lists qualities of the Corundum gem type, including stone colors, common names, meanings, gemstone hardness and more.

2024年9月25日 · Black corundum is a material mainly composed of aluminum oxide (Al2O3), containing a large amount of impurities such as silicon oxide and titanium oxide, presenting a black color. It is a new environmentally friendly material with high melting point (2050 ℃) and high hardness (Mohs hardness of 9).