beryl
Concise Oxford English Dictionary © 2008 Oxford University Press:
beryl /ˈbɛrɪl/
▶noun a transparent pale green, blue, or yellow mineral consisting of a silicate of beryllium and aluminium, sometimes used as a gemstone.
– origin ME: from OFr. beril, via L. from Gk bērullos.
'beryl' also found in these Oxford entries:

