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A notebook, pen, mobile phone with compass app and a digital camera sit on top of a map.
Article
The Stories Behind the Photos: A Gigantic Aquamarine and ‘Gaudy’ Nature

Gemmological photojournalist Robert Weldon shares the stories behind some of his favourite photos.

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Collecting amber along the Baltic sea
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Historical Reading List: Baltic Amber

Amber has been found in various parts of the world, but the main historical source is the land that surrounds the Baltic Sea.

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Miners use shovels and sluicing equipment to search for diamonds near the Vaal River in South Africa.
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Historical Reading: The Diamond Fields of South Africa: Part 2 (1893-2014)

Within a few years of their discovery, the diamonds deposits of South Africa produced more diamonds than had come from India in two millennia.

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An early black and white photo that shows deep trenches dug into the ground in the search for diamonds. Ladders and ropes help the miners excavate and traverse the mine.
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Historical Reading: The Diamond Fields of South Africa: Part 1 (1868-1893)

The discovery of diamonds in South Africa in early 1867 marked the start of an historic period of diamond exploration.

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Article
Historical Reading: The California Gold Rush

The California gold rush − the largest gold rush in the history of the world − changed the social, economic, political and cultural history of the American West.

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An Introduction to Simulants or Imitation Gem Materials

Imitation diamonds such as CZ and moissanite have been popular for decades. Learn about their properties and how they compare to diamonds.

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HPHT and CVD Diamond Growth Processes: Making Lab-Grown Diamonds

While more people are becoming familiar with lab-grown diamonds, many still don’t know how they are actually made. Learn about the two diamond growth processes, HPHT and CVD.

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Three pieces of labradorite with yellow, blue and green flashes of color.
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Optical Effects of Phenomenal Cabochons

Learn how the structure, inclusions and properties of some gemstones interact with light to create unusual visual effects.

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Article
GIA's Gübelin Gem Project: Corundum

Ruby and sapphire (usually blue, but also in every other colour) have been the most important coloured gemstones for several thousand years. Originating historically in south-east and central Asia, and more recently in eastern Africa, these coloured varieties of the mineral corundum have been much sought as gems because of their rarity, colour and durability. Gem corundum can display asterism and chatoyancy due to the presence of oriented mineral inclusions, and in some cases, a change of colour when viewed under different light sources.

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Opal
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Opal Quality Factors

Individual opals are as diverse as snowflakes or fingerprints and can vary widely in appearance and quality. Learn about the factors that make opals so desirable!

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