Colour, origin, treatment
Gemstones
Coloured stones are where jewelry becomes personal. Here is how the good ones are judged, why a certificate matters more than a carat and which stones survive a life on your hand.
The guides
Gemstones
The big three, gemstone treatments decoded, hardness and everyday wear, why origin changes the price. Plus sixteen gemstone profiles with hardness, colour, birthstone month and care. The Paliana gemstone guides.
Photo: MessikaMessika
Messika Terres de Contrastes: High Jewelry around Botswana’s Largest Blue Diamond
Messika Terres de Contrastes: the Okavango Blue necklace with Botswana’s largest blue diamond, 20.46 carats, plus a 12.81-carat emerald, a black opal and a rubellite.
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Colour first, everything else second
The Big Three: Ruby, Sapphire and Emerald
How ruby, sapphire and emerald are judged, which colours the trade pays for, what the famous origins mean and how much a fine stone really costs per carat.
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What was done to the stone
Heated, Oiled, Filled: Gemstone Treatments Decoded
Almost every gemstone in a shop has been treated. Some treatments are accepted and permanent, some are hidden and reversible. Here is what each one does, how it is disclosed and how it moves the price.
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Which stones survive your life
Hardness, Toughness and Everyday Wear
The Mohs scale tells you what scratches what; it does not tell you what breaks. Here is how hardness, toughness and stability decide which stones suit a daily ring and how to clean each of them.
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Where a stone was born
Why Origin Matters: Kashmir, Burma, Colombia
The same colour from two mines can differ in price by a factor of five. How laboratories determine origin, which names carry premiums and when origin should not matter to you at all.
Read the guideGemstones A to Z
Sixteen stones, side by side
Filter by birthstone month, hardness or daily-wear suitability. Click a stone for its full profile.
No stone matches every filter. Loosen one.
The tool for this section
Gemstone Comparator
Compare up to three gemstones side by side: hardness, toughness, daily-wear suitability, price tier, treatments, origins and care.
Side by side
Gemstone Comparator
Compare up to three gemstones side by side: hardness, toughness, daily-wear suitability, price tier, treatments, origins and care.
OpenThe 4Cs, priced
Diamond Price Estimator
Estimate the retail price of a natural or lab-grown diamond from carat, colour, clarity, cut and shape, and see what a buyer would typically offer for it.
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Sell Diamonds and Gemstones
Sell a diamond ring, a loose diamond, a sapphire, ruby or emerald. Describe carat, certificate and setting and receive offers from vetted gemstone buyers.
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