Articles

In search of ruby and sapphire on the lost Isle of Madagascar.

The examination of a yellow sapphire provides a lesson in the power of gemological microscopy.

Introducing the blue filter as a gemological tool to separate natural and Verneuil synthetic yellow sapphires.

Virtually all gemologists are aware of the curved growth lines and gas bubbles in Verneuil (flame-fusion) synthetic corundum, but few understand exactly why they occur and how they are distributed in these stones. This article clarifies these important identifying features.

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.

Many gemologists have difficulty mastering the direct-vision spectroscope. This article eases the pain.

One of the greatest gemological challenges is determining if a ruby or sapphire has been heat treated. UV fluorescence can assist in that identification, as well as detecting fillers in emerald.

The role of fiber-optic lighting in gemological microscopy.

A discussion of how inclusion patterns mimic crystallographic symmetry in ruby and sapphire.

A discussion of the definition of padparadscha sapphire, from early to modern times, along with the difficulty in standardizing such definitions.