It had occurred to me that something was odd about this scarab. I had seen it many times while reading. The color of the scarab seemed unusual. I suppose feldspar was not immediately available to the craftsmen who created this masterpiece, so they settle on using this meteoric glass. I wouldn't put it past Tutankhamun to want something unusual incorporated into his jewelry, coming from a family who had ignored the rules of tradition of any medium. As much as Tutankhamun tried to disassociate himself from the ways of his father, I suspect he enjoyed a bit of artistic freedom himself. After all, the presence of the Aten and the portly belly-skinny limb rendering of his own likeness were evident in his artifacts.
This brings to mind the age of the Sphinx, but that's another, very long-winded, discussion.