Spinel

Completely pure spinel is colorless and has been used to as a diamond substitute in jewelry. Colored spinels get their color from impurities; the most valuable red and blue ones are hard to tell from ruby and sapphire. The natural stone also comes in green, violet, black, and orange. Occasional spinels with asterisms have been found.

Synthetic spinel has been manufactured since 1915 and is commonly used in cheap jewelry (Joel Arem's Gems specifically mentions 'class rings and inexpensive birthstone jewelry, usually (erroneously) labeled in quotes, such as "tourmaline" or "topaz."' With a rating on the Mohs hardness scale of 8, spinel works well in jewelry.

Spi*nel" (?), Spi*nelle" (?), n. [F. spinelle, or LL. spinellus, perhaps from L. spina a thorn, a prickle, in allusion to its pointed crystals.] Min.

A mineral occuring in octahedrons of great hardness and various colors, as red, green, blue, brown, and black, the red variety being the gem spinel ruby. It consist essentially of alumina and magnesia, but commonly contains iron and sometimes also chromium.

⇒ The spinel group includes spinel proper, also magnetite, chromite, franklinite, gahnite, etc., all of which may be regarded as composed of a sesquioxide and a protoxide in equal proportions.

© Webster 1913.

Spin"el (?), n.

Bleached yarn in making the linen tape called inkle; unwrought inkle.

Knight.

© Webster 1913.