Gem Knowledge

Understanding Specific Gravity and Why it is Vital to Gemmologists

Specific Gravity is a vital test that all gemmologists need to be aware of. Here, Gem-A Gemmology Tutor, Dr Juliette…

Historic Uses of Topaz Gemstones in Jewellery

Jewellery historian and valuer, John Benjamin FGA DGA FIRV, shares insights into the history of topaz gemstones in jewellery, including…

Understanding Play of Colour and Patterns in Opal Gemstones

Did you know the colours and patterns in an individual opal gemstone can drastically alter its value and desirability? Here,…

What Does It Mean When a Specimen Is Opalised?

Senior Gemmology Tutor Pat Daly FGA DGA explores the phenomenon of opalisation, how it occurs and where you can expect…

The Fascinating History of Antique Turquoise Jewellery

In his third Gemstone Conversations column for Gems&Jewellery, Jewellery Historian and Valuer John Benjamin FGA DGA FIRV explores the fascinating…

Getting Started with Quartz Inclusions

Do you know your calcite inclusions from your dumortierite, epidote, fluorite and rutile? Here, Charles Bexfield FGA DGA EG explores…

Understanding Iridescence in Gemstones

Iridescence has to be one of the most mesmerising and magical optical effects seen in gemstones. But have you ever…

Hidden Treasures: Highlights of Gem-A's Gemstones and Minerals Collection

Locked away in the vaults of Gem-A HQ in London is an assortment of breath-taking treasures that form Gem-A’s Gemstones…

Understanding the Cat's Eye Effect in Gemstones

Chatoyancy is the gemmological name given to the curious optical effect in which a band of light is reflected in…

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