Gemstone Knowledge
SOOKJAI KNOWLEDGE
Gemstone Knowledge
A considered guide to gemstones — from colour and cut to origin, treatment and the stories behind each stone.
Colour · Spinel
Grey Spinel: Understanding Tone, Undertone and Character
Grey spinel is far more varied than one neutral shade. Learn how light-to-dark tone, blue or violet undertones, lighting, cut and metal context shape the character of grey spinel—and why there is no single best grey.
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Sapphire · Colour
Madagascar Sapphire: Colour, Character and Origin
Madagascar sapphire spans far more than one familiar look. Explore the blue-green character traders sometimes associate with the origin, its wide range of sapphire colours, the brighter character seen in some Madagascar rubies, and why appearance alone cannot establish where a stone came from.
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Sapphire · Colour
Why Sapphire Colour Changes Under Different Lighting
The same sapphire can look different in daylight, studio light and warm indoor lighting without the stone itself changing. Learn how illumination, brightness, colour zoning and camera processing affect the colour we see—and why this is not automatically the same as colour-change sapphire.
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Sapphire · Colour
Parti Sapphire: When More Than One Colour Shares a Stone
Parti sapphire makes visible colour zoning part of the stone’s character. Learn how different colours form within one sapphire, how cutting changes the pattern we see, why teal and parti can overlap, and how colour distribution can shape a jewelry design.
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Sapphire · Colour
Cornflower Blue Sapphire: What Defines the Colour?
Cornflower Blue is more than a lighter version of Royal Blue. Explore its historic association with Kashmir sapphire, vivid and often velvety character, laboratory terminology, and what the name does—and does not—tell you.
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Sapphire · Colour
Teal Sapphire: Understanding Blue-Green Sapphire
Teal sapphire sits where blue and green meet, but there is no single teal shade. Explore blue-dominant, balanced and green-dominant characters, colour zoning, parti sapphire, lighting, origin and how teal works in jewelry.
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Sapphire · Colour
Padparadscha Sapphire: Understanding One of Sapphire’s Rarest Colours
Padparadscha describes a rare pink-and-orange colour range in sapphire, but not every peach or salmon sapphire qualifies. Learn what the term means, why laboratory criteria and colour stability matter, and how to read a Padparadscha claim.
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Sapphire · Colour
Royal Blue Sapphire: What Does the Name Actually Mean?
Royal Blue is one of sapphire’s best-known trade colour names, but it is not a universal grade. Learn what the term describes, why laboratory criteria matter, and what the name does—and does not—tell you about a sapphire.
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Sapphire · Colour
How to Choose a Blue Sapphire
Choosing a blue sapphire is not about finding one universally better shade. Explore how different blue characters feel, how they work with jewelry and metals, and how to choose a sapphire that suits the way you want to wear it.
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Sapphire · Colour
Sapphire Colours: From Blue to Pink, Yellow and Beyond
Explore the colour range of sapphire, from familiar blues to pink, yellow, green and other hues, and understand how hue, tone and saturation shape what we see.
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