Yesterday I posted that a company called “Spectral Gems” used to
publish a nice plastic coated sheet of on how various
common gemstones tolerate heat, pickling, ultrasonics, etc. I didn’t
have the address at the time but here it is. These people have a
pretty good selection of stones, a nice looking catalog, good for the
showroom with triple key pricing, etc. I find their prices a bit
high, but often resort to them when I’m looking for something
Spectral Gems, Inc.
P.O. Box 12303
Birmingham, MI USA
Toll Free: 1-800-637-4367
Ask them about their “Gemstone Characteristics and Durability Guide”.
David L. Huffman