Hairlike Inclusions in Benitoite
The authors recently examined a 3.55 ct benitoite that featured whitish hairlike inclusions throughout the stone (see above). The inclusions were too thin to be identified by Raman spectroscopy.
Gem-quality benitoite has been extracted from a single mine in California and is reported to occur with natrolite gangue in altered blueschist within serpentinite. Minerals found within benitoite include actinolite-tremolite, aegirine-augite, diopside, serandite pseudomorphs, neptunite, joaquinite, albite, apatite, and djurleite (B.M. Laurs et al., “Benitoite from the New Idria District, San Benito County, California,” Fall 1997 G&G, pp. 166–187). Therefore, the hairlike inclusions in this stone could be natrolite, chrysotile (white asbestos), or tremolite, which have whitish colors and acicular or fibrous crystal habits.
