Featured Articles

Recent studies show that the gem known throughout the non-Chinese world as "jadeite" jade is actually a rock composed of three major mineral components – jadeite, omphacite and kosmochlor. These components grow in a submicroscopic aggregate with grains so small that normal lab instruments (FTIR, Raman) cannot easily determine the true composition. As a result, China's gem trade has adopted the traditional term "fei cui" (pronounced 'fay choy') to cover all the pyroxene jades. Lotus Gemology has done the same starting on 1 July 2023, dropping the names jadeite/omphacite/kosmochlor in favor of the scientifically more correct "fei cui."

Hands-on workshop looking at different types of jade.

Billie Hughes & Wim Vertriest report the results from their low-temperature heat treatment experiments on Burmese ruby.

Greasy Business • The Ongoing Fraud of Oiled Gems

There are many benefits to using a long-wave UV torch when testing ruby and sapphire. Here are a few examples.

Jade has a long and varied nomenclatural history, with its definition altered in the current age for practical and cultural reasons. This paper examines the hardness of "fei cui" (pyroxene jade) and presents the findings in a simplified format based on empirical evidence and theoretical principles, while also considering the jade hardness data available in literature.

Color types such as "pigeon's blood," "Paraíba" and "cobalt blue" have become wildly popular in the gem trade. But there is a vast difference between coining such terms and applying them in a way that is both consistent and logical. Richard Hughes casts a critical eye at the subject.

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.

Detection of heat treatment below 1200°C in ruby and sapphire can present challenges to gemologists. In this study, the authors heated Burmese ruby samples and detailed the features that help in the detection of heat treatment.

A truth that's told with bad intent, beats all the lies you can invent.

—William Blake [1757–1827], Proverbs, Line 95

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.

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.

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 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.

Why should Hugh Hefner be the only one to enjoy twins? This special Hyperion Inclusion Gallery features images from the Lotus Gemology Hyperion Inclusion Database, but are shown as pairs, all the better to compare one form of beauty with another.

Developing a comprehensive colored stone grading system has been the dream of gemologists since the late 1970's, but despite a number of valient attempts, we are no closer to the goal today than we were four decades ago. This article examines the various problems of colored stone grading, explaining why the challenges are at least an order of magnitude greater than the grading of diamonds.

A brief description of the color types for ruby and sapphire used at Lotus Gemology.