Hi @Richard_Hart3,
It wasn’t my intention to suggest that merely the presence of a sugary girdle proved the stone was a diamond, but that if magnification showed several characteristics of diamond, then it is a diamond. For instance, I don’t know of other stones that have naturals. Feathers in diamonds (fractures) are characteristic of diamonds. A lack of scratches indicates hardness. Diamond’s dispersion is fairly high, but lower than that of CZ or of strontium titanate. Of course, one would need some experience looking at many diamonds before using this approach. If the stone is quite flawless, there might not be any clues and then another approach would be necessary.