How does one go about choosing a good gem testing lab? The gemologists at Lotus Gemology provide the following guide to help customers make the best decisions when choosing a good gem testing lab.

Oil treatment has a significant impact on the appearance of an apatite.

Hogbomite-filled dislocations in a Vietnamese spinel.

A web-like fingerprint creates a maze-like pattern in spinel.

The internal world never fails to amaze, as witnessed by this incredible video of a negative crystal in a Sri Lanka sapphire.

This article discusses the challenges of identifying inclusions based on observation alone. While certain features can help narrow down the possibilities, other methods such as micro Raman help identify inclusions with a greater degree of certainty.

When a red spinel and a tanzanite were submitted for testing, oil was found in the fissures. Removal of the oil resulted in a startling deterioration in clarity.

A large black star sapphire was brought in for testing. Two large pits on the base were carefully filled with brown dopping varnish. After removal of the varnish with alcohol, it was found that a large portion of the base had been filled with a lead glass.

A discussion of the literature of ruby and sapphire (corundum), with particular emphasis on the most collectible books covering ruby and sapphire around the world.

This article discusses the use of handheld long-wave ultraviolet torches with the microscope. It has been found that these have tremendous utility in identifying and characterizing certain oiled gemstones, such as emerald, tourmaline, etc.