BGO12 Bismuth Germanate Facet Rough pyro Note that the camera exaggerates

Note that the camera exaggerates the red at the expense of the green--they do look better in person

when found

Most of these have voids inside

and Nd alone gives a purple shifting color

BGO12 Bismuth Germanate Facet Rough pyro Note that the camera exaggeratesThese are BGO 12 aka Bismuth Germanate facet rough. This is a real cool rarity in the gem world. Bismuth Germanate (in this case, specifically Bi3Ge4O12 aka evlitine) is valued as an optical substrate because of its highly unusual electrooptical properties. It has exceptionally good optical properties too, with (as far as we can tell the literature is weak) an RI of 2. 15 and dispersion of 0. 1. Cut stones are incredibly beautiful with high brilliance