- a brilliant green variety of andradite garnet, used as a gem.
Origin of demantoid
Also called Uralian emerald.
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018
Examples from the Web for demantoid
Demantoid is regarded as a lime-iron garnet, coloured probably by a small proportion of chromium.
The hardness is only 6.5, or lower even than that of quartz—a character rather adverse to the use of demantoid as a gem.
The demantoid garnet (sometimes called "olivine" in the trade).
The demantoid garnet is also very soft as compared with emerald (61⁄2 as against nearly 8).
Perhaps the adoption of the name "Demantoid" might relieve the situation.
- a bright green variety of andradite garnet
C19: from German, from obsolete Demant diamond, from Old French diamant + -oid