- Gehlenite and Hyalite Opal (fl) (?)
- Thumbnail, 2.6 x 1.8 x 1.7 cm
- nr. Tin Mountain, Death Valley Nat'l Park, Inyo Co., California, USA
- Ex. Kay Robertson
Exceptionally large for the species, this may very well be the finest Gehlenite specimen I have seen, from anywhere. The vitreous luster on the brownish-gold crystal is almost metallic, not unlike what you see in a fine Mica. The form on this prismatic crystal is excellent, with striated faces and a very smooth termination, which may be cleaved. There is an unknown mineral near the base that fluoresces a bright neon green, leading me to think it is likely Hyalite Opal. Gehlenite, an uncommon silicate, has never been so well-represented in specimens I have seen for sale. This is highly unusual, and in any case especially unusual for the USA.