corundum

Noun

Meaning

The earth alumina, as found native in a crystalline state, including sapphire, which is the fine blue variety; the oriental ruby, or red sapphire; the oriental amethyst, or purple sapphire; and adamantine spar, the hair-brown variety. It is the hardest substance found native, next to the diamond.

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Phrases with the word

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Examples

After the 18th century the word ruby was only used for the red gem variety of the mineral corundum and the word spinel came to be used. Source: Internet

Among the natural gems only moissanite and diamond are harder, with diamond having a Mohs hardness of 10.0 and moissanite falling somewhere in between corundum (ruby) and diamond in hardness. Source: Internet

All other hues of the gem species corundum are called sapphire. Source: Internet

Dark blue sapphire, probably of Australian origin, showing the brilliant surface luster typical of faceted corundum gemstones. Source: Internet

For softer materials silicon carbide, garnet (emery) or corundum can be used in place of the diamond. Source: Internet

Hydrothermal lab-grown alexandrite has identical physical and chemical properties to real alexandrite. citation Some gemstones falsely described as lab-grown synthetic alexandrite are actually corundum laced with trace elements (e. Source: Internet

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