Lotus • Articles from Lotus Gemology

Some yellow sapphires contain unstable color centers. The following discussion outlines case studies of stones that faded after testing in the lab, and how color may be restored.

Short-wave fluorescent illumination provides a useful tool to spot curved banding in flame-fusion synthetic sapphire.

Blue apatite crystals in garnet.

An apatite crystal appears to float, suspended over a rutile silk cloud in a star sapphire.

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.

Discussion of gem treatment disclosure and its somewhat difficult history.

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.