Fiber-optic lighting is one of the most useful form of lighting in the gemological laboratory. With it, we are able to see inclusions that would otherwise be invisible.

The optical properties of crystals are intimately related to their crystal structures. This article examines the precise relationship between optic character and sign and crystal structure.

Links to websites related to gemology, gemstones, minerals and jewelry.

The use of Fourier-Transform Infrared Spectroscopy (FTIR) in gem identification, with examples of sapphire & jadeite.

Inclusions are among the most important features for identifying ruby and sapphire. This is the chapter on ruby and sapphire inclusions from Richard Hughes' 1997 book, Ruby & Sapphire.

Ruby & Sapphire  •  A Gemologist's Guide Richard W. Hughes, with Wimon Manorotkul & E. Billie Hughes  |  2017 Designed as a companion to Rub...