Difference between olivine and nakhlite
- a mineral consisting of magnesium iron silicate; a source of magnesium
Gem varieties include topazolite, similar in color and transparency to topaz; demantoid, a green variety with a high dispersion and adamantine luster, sometimes miscalled olivine and Uralian emerald; and black melanite.
Myles L. Miller, Scott S. Hughes, 2009, Mixing primitive and evolved olivine tholeiite magmas in the Eastern Snake River Plain, Idaho
The use of "demantoid" alone, if a noun may be made from the adjective, would avoid both the confusion with the mineral olivine, and the cheapening effect of the word garnet, and would at the same time suggest some of the most striking properties of the material.