Lotus • Articles from Lotus Gemology

From Fei Cui to Jadeite and Back | Questions and Answers
From Fei Cui to Jadeite and Back | Questions and Answers
- Lotus Gemology
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 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."

Lenny Cram's Opal Mine | Fun Down Under
Lenny Cram's Opal Mine | Fun Down Under
- Richard W. Hughes
The believe-it-or-not story of Australia's Lenny Cram and his opal mine in a mason jar.

Describing Color in Gems | A Fool's Guide
Describing Color in Gems | A Fool's Guide
- Richard W. Hughes
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 on the subject.

Spinel Inclusions | An Exercise in Aesthetics
Spinel Inclusions | An Exercise in Aesthetics
- E. Billie Hughes, John I. Koivula, Wimon Manorotkul, Nathan Renfro and Richard W. Hughes
To the jeweler, spinel is famous for its vivid colors. But for the gemologist, this gem is unlike any other. Its extreme hardness allows a fine polish. Couple this with single refraction, which eliminates the image blurring found in most other gems, and a varied landscape of inclusion subjects, and the result is an unparalleled canvas of delight for the photomicrographic artist.

Madagascar Sapphire | Low-Temperature Heat Treatment Experiments
Madagascar Sapphire | Low-Temperature Heat Treatment Experiments
- E. Billie Hughes and Rosey Perkins
Madagascar has become one of the world’s top sources of fine blue sapphire in recent times. In addition to beautiful untreated material, increasing numbers of treated stones have appeared in the market. Some have been heated to relatively low temperatures, below 1350°C, to lighten their color. To help separate unheated and heated Madagascar sapphire, the authors performed experiments to document the changes they undergo with low-temperature heat treatment in air, which is an oxidizing atmosphere.

Gem Inclusion Pairs | Hyperion Siamese Twins
Gem Inclusion Pairs | Hyperion Siamese Twins
- Lotus Gemology
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.

Mogok Revisited | A Brief Stay in Heaven
Mogok Revisited | A Brief Stay in Heaven
- E. Billie Hughes
An account of a 2013 visit to Mogok – Myanmar's fairy-tale wonderland.

Downtown | Gem Hunting in Tanzania
Downtown | Gem Hunting in Tanzania
- Richard W. Hughes & Vincent Pardieu
Since the late 1960's, East Africa has been home to some of planet earth's greatest gem discoveries. And yet, little has been written about certain of these finds. In the autumn of 2007, the authors set out to fill in the gaps, specifically regarding Tanzania's Mahenge, Songea and Tunduru regions.

Padparadscha Sapphire & the Ownership of Words
Padparadscha Sapphire & the Ownership of Words
- Richard W. Hughes
A discussion of the definition of padparadscha sapphire, from early to modern times, along with the difficulty in standardizing such definitions.

Oiled Spinel & Tanzanite | Shocking Revelations
Oiled Spinel & Tanzanite | Shocking Revelations
- Richard W. Hughes
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.

Gemology in the 21st Century | Betwixt Two Worlds
Gemology in the 21st Century | Betwixt Two Worlds
- John L. Emmett & Richard W. Hughes
Traditional gemology considers itself a science, but typically omits a key element of the scientific method. And is gemology simply a science, or something more? Read on to learn the answer…

Rutile in Corundum | Following the Silk Road
Rutile in Corundum | Following the Silk Road
- John I. Koivula & Richard W. Hughes
A discussion of rutile silk in corundum and its use in detecting artificial heat treatment. Careful examination of these "silk" inclusions can provide vital clues to unmask heated gems.

Detecting Corundum Fillers with the Long-Wave UV Torch
Detecting Corundum Fillers with the Long-Wave UV Torch
- E. Billie Hughes
There are many benefits to using a long-wave UV torch when testing ruby and sapphire. Here are a few examples.

The Hardness of Fei Cui Jade | A Gemological Perspective
The Hardness of Fei Cui Jade | A Gemological Perspective
- Kaylan Khourie
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.

Yellow Sapphires with Unstable Color
Yellow Sapphires with Unstable Color
- E. Billie Hughes
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.

Canary in the Ruby Mine | Low-Temperature Heating of Burmese Ruby
Canary in the Ruby Mine | Low-Temperature Heating of Burmese Ruby
- E. Billie Hughes & Wim Vertriest
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.

Meet the Extraordinary 40 | Richard Hughes Honored by Jewellery News Asia
Meet the Extraordinary 40 | Richard Hughes Honored by Jewellery News Asia
- E. Billie Hughes
Meet the Extraordinary 40 • Richard Hughes Honored by Jewellery News Asia

Curved Banding in Flame-Fusion Synthetic Sapphires
Curved Banding in Flame-Fusion Synthetic Sapphires
- E. Billie Hughes
Short-wave fluorescent illumination provides a useful tool to spot curved banding in flame-fusion synthetic sapphire.

Blue Apatite in Tanzanian Garnet
Blue Apatite in Tanzanian Garnet
- E. Billie Hughes
Blue apatite crystals in garnet.

Apatite in Blue Sapphire
Apatite in Blue Sapphire
- E. Billie Hughes
An apatite crystal appears to float, suspended over a rutile silk cloud in a star sapphire.