Sphene vs. Demantoid part 3
I talked to Victoria about my hypothesis that birefringence could be what makes Sphene look more dispersive than Demantoid, despite Demantoid having a higher dispersion than Sphene.
Birefringence is when the light splits within a stone. If you look at a lined sheet of paper through a birefringent stone, the lines become doubled. I thought, perhaps, it then doubles the sparkle.
Victoria says the answer to that is no.
Well, she's the gemologist. I don't understand why not, though.
So it just has to be that the Sphene I saw was gigantic and had a spectacularly excellent quality cut, and the demantoids I saw were teeny, possibly more included, and more poorly cut. I have seen larger demantoids that still did not sparkle like this Sphene, but given the size and quality of the piece, and the fact that it was sitting in a showcase at Neiman Marcus NorthPark in Precious Jewels... it just had to have been cut by someone who knew what the fuck they were doing, and took incredible care to make this stone - probably the only example some people will EVER see of a Sphene in person - to be completely, inhumanly flawless.
I can't wait to delve further into identifying birefringence in GIA training...
Birefringence is when the light splits within a stone. If you look at a lined sheet of paper through a birefringent stone, the lines become doubled. I thought, perhaps, it then doubles the sparkle.
Victoria says the answer to that is no.
Well, she's the gemologist. I don't understand why not, though.
So it just has to be that the Sphene I saw was gigantic and had a spectacularly excellent quality cut, and the demantoids I saw were teeny, possibly more included, and more poorly cut. I have seen larger demantoids that still did not sparkle like this Sphene, but given the size and quality of the piece, and the fact that it was sitting in a showcase at Neiman Marcus NorthPark in Precious Jewels... it just had to have been cut by someone who knew what the fuck they were doing, and took incredible care to make this stone - probably the only example some people will EVER see of a Sphene in person - to be completely, inhumanly flawless.
I can't wait to delve further into identifying birefringence in GIA training...