Guides & market insights
Gemstone Guides
Plain-English guides to the world’s finest coloured stones and how they hold their value, written by dealers.
Spinel
Spinel: the most underrated gem in the world
Hardness 8, usually untreated, colours that stop you in your tracks. The colours ranked, the origins that matter and how to choose one.
Read the guideCertification
How to read a gemstone lab report
GRS, SSEF, Gübelin and AGL decoded: treatment codes, pigeon’s blood and royal blue, and how to check a report is genuine.
Read the guideInvesting
Coloured gemstones as an investment: a history of prices
Ruby, sapphire, spinel, Paraíba and emerald: the real numbers, why fine unheated stones keep rising, and an investment-grade checklist.
Read the guideRuby
The king of gems: ruby
Pigeon’s blood, Burma vs Mozambique, and why heat matters so much.
Sapphire
Sapphire, beyond blue
Royal blue, Kashmir, Ceylon, padparadscha and the fancy colours.
Emerald
Emerald: the garden within
Colombia vs Zambia, oil and clarity, and what to look for.