Chart: Inclusions in Natural, Synthetic, and Treated Sapphire
Provides a visual guide to the internal features of natural, synthetic, and treated sapphires.
Phenomenal Gems
A look at the most popular phenomenal gems exhibited at the 2025 Tucson gem shows.
Paraíba Tourmaline Melee: An Entry-Level Market Perspective
Color Characteristics of Blue to Yellow Beryl from Multiple Origins
Discusses the features of alkali elements and their influence on the color of blue to yellow beryl.
Phenomenon Resembling Play-of-Color in Sapphire
A phenomenon resembling play-of-color was seen in a 4.13 ct unheated sapphire recently examined by the author.
Heliodor with a Large Schorl Inclusion
Inclusion Resembling a Gada in Diamond
Large Stellate Dislocation in Spinel
Rainy Lakeside City in Peridot
A Red Herring in a Red Garnet
Gemological Characteristics of Saltwater Cultured Pearls Produced After Xenotransplantation
X-ray Computed Microtomography: Distinguishing Natural Pearls from Beaded and Non-Beaded Cultured Pearls
The distinction of natural from cultured pearls traditionally has been based on X-radiography.
Color Grading of Colored Diamonds in the GIA Gem Trade Laboratory
HPHT-Processed Diamond Fraudulently Represented as Untreated
An HPHT-treated round brilliant diamond with an inscription that presents as a GIA report number is found to be inconsistent with the institute's report, previously issued for an untreated diamond.
A Useful Technique to Confirm the Hydrophane Nature of Opal
Observing a water drop’s interaction with opal, as well as refractive index, can confirm a specimen’s hydrophane nature with less risk of breakage than total immersion.
Hydrophane Opal Treatment
An opal rough is immersed in water and treated with oil and Opticon to observe effects on transparency and play-of-color.
Identification of “Pistachio” Colored Pearls Treated by Ballerina Pearl Co.
A report on the color treatment process for these intensely greenish yellow to yellowish green cultured pearls and the techniques for identifying them.
Spectral Reflectance and Fluorescence Characteristics of Natural-Color and Heat-Treated “Golden” South Sea Cultured Pearls
A comparison study was made between the yellow and white nacre of the gold-lipped Pinctada maxima oyster shell and 65 yellow cultured pearls.
A Pearl Identification Challenge
Two pearls presented a unique challenge, as testing at three different gemological laboratories could not conclusively identify them as natural or cultured, determine a freshwater or saltwater growth environment, or specify the producing mollusk.
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