sphene

sphene (SFEEN) - n., a mineral, a calcium titanium nesosilicate (CaTiSiO₅) with brown, yellow, or green crystals and sometimes used as a gemstone, also called titanite.


Or rather, the International Mineralogical Association has deprecated the name sphene in favor of titanite, but sphene is often still used especially for the gemstone. Coined in 1801 in French as sphène by mineralogist René Just Haüy, from Ancient Greek sphḗn, wedge, because its crystals are often wedge-shaped.


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---L.