spinel

/spi-nel, spin-l/US // spɪˈnɛl, ˈspɪn l //UK // (spɪˈnɛl) //

尖晶石,尖晶石类,尖晶石类的

Definitions

n.名词 noun

1
- : any of a group of minerals composed principally of oxides of magnesium, aluminum, iron, manganese, chromium, etc., characterized by their hardness and octahedral crystals.
- : a mineral of this group, essentially magnesium aluminate, MgAl2O4, some varieties being used as gems.

The rock—which also contains the plain-old mineral plagioclase—includes pink spinel, a prized jewel on Earth.
The rubies of Burma are found in crystalline limestones and are constantly accompanied by precious spinel (or balas-ruby).
Some of the alumina and iron oxide may occasionally be chemically combined, so as to form an iron spinel, or hercynite.
Then follows the topaz, which, with spinel and chrysoberyl, has a hardness of 8; whilst quartz falls a degree lower.
Mention has been made above of a stone frequently substituted for the true ruby, called the “spinel” or “balas” ruby.
The spinel and ruby occur together in nature, stones from Burma being as often spinel as true Oriental ruby.