from The American Heritage® Dictionary of the English Language, 4th Edition
- n. A natural beryllium silicate, Be2SiO4, occurring as vitreous crystals sometimes used as gems.
from Wiktionary, Creative Commons Attribution/Share-Alike License
- n. A clear glassy mineral, a silicate of glucina, occurring in rhombohedral crystals and sometimes used as a gem.
from the GNU version of the Collaborative International Dictionary of English
- n. A glassy colorless mineral occurring in rhombohedral crystals, sometimes used as a gem. It is a silicate of glucina, and receives its name from its deceptive similarity to quartz.
from The Century Dictionary and Cyclopedia
- n. A rare mineral occurring in transparent rhombohedral crystals, colorless to wine-yellow, and having a vitreous luster.
Greek phenāx, phenāk-, impostor + -ite1.(American Heritage® Dictionary of the English Language, Fourth Edition)
Ancient Greek impostor, deceiver, because of its resemblance to quartz. (Wiktionary)