The 3309 cm–1 Series in Sapphire and Ruby: A Focus on FTIR Peak Position Variation

Investigates the correlations between peak positions in the 3309 cm–1 series with trace element concentrations for ruby, metamorphic and basalt-related blue sapphire, and laboratory-grown sapphire.

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Emeralds in Catherine de’ Medici’s Pendant: An Unexpected Geographic Origin

Archival research and gemological characterization reveal the geographic origin of two emeralds set in a pendant linked to Catherine de’ Medici, Queen of France from 1547 to 1559.

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A Study of the Winston Red: The Smithsonian’s New Fancy Red Diamond

Presents the first scientific and historical study conducted on the 2.33 ct Winston Red, the fifth-largest known Fancy red diamond in existence.

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Update on Montana’s Rock Creek Sapphire

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Rare Faceted Väyrynenite

Uniquely saturated examples of the collector stone were on display at GJX.

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Paraíba Tourmaline Melee: An Entry-Level Market Perspective

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Black Opal with Unique Play-of-Color

A black opal cabochon set in a ring displays vivid orange play-of-color.

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Tucson 2025 Overview

A summary of the findings at the 2025 Tucson gem shows.

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Phenomenal Gems

A look at the most popular phenomenal gems exhibited at the 2025 Tucson gem shows.

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In Memoriam: Glenn Lehrer (1953–2024)

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In Memoriam: Alan Hodgkinson (1937–2024)

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Analytical Techniques in Gemology: A Historical Overview

Gemology has become a highly technical field employing analytical instruments for gem testing, driven by the need to address increasingly complex identification challenges in the marketplace.

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