It does look like stone and whatever it is probably needs a good polish. Maybe obsidian, since VCA is replacing TE with obsidian on some of the clips?
Tortoise shell looks fab, but there is no way I'd wear it now. I wonder how many ivory necklaces are out there in collections? You can't buy/sell ivory at all in Hawaii anymore. Not even any exceptions for vintage Ming's ivory jewelry. I wonder if VCA would ever consider using buffalo horn in place of tortoise shell in the alhambra line. It might draw in the horn lovers from H, and is so much more sustainable.