Gem Education
Gemstone Guide
A reference guide to the world's finest precious and collector gemstones — what makes each unique and why they matter.
Ruby
Burma, Sri Lanka, Mozambique
The "King of Gems" — prized for pigeon blood red. Chromium gives rubies their colour. Fine unheated Burmese rubies are among the most valuable gemstones on earth.
Emerald
Colombia, Zambia, Brazil
Intense green from chromium and vanadium. Almost all emeralds contain jardin (garden) — a network of inclusions that is accepted and expected in the trade.
Spinel
Burma, Sri Lanka, Tanzania
Often mistaken for rubies and sapphires throughout history. Spinels come in vivid reds, pinks, and blues. The Black Prince's Ruby in the British Crown Jewels is actually a spinel.
Alexandrite
Russia, Sri Lanka, Brazil
The colour change chameleon — green in daylight, red under incandescent light. Fine alexandrite with strong colour change is extremely rare and expensive.
Tsavorite
Tanzania, Kenya
A vivid green garnet discovered in 1967 in Tsavo National Park. No treatment required — all colour is natural. Growing in popularity as a fine emerald alternative.
Tourmaline
Brazil, Nigeria, Mozambique
One of the most colour diverse gem species. Paraíba tourmalines — neon blue green from copper — are among the most sought after coloured stones in the world.
Key Principle
Colour is King
For coloured gemstones, colour is the primary value driver — accounting for up to 60% of a stone's worth. Saturation, hue, and tone all contribute. A well-cut stone with vivid, even colour will always outperform a larger, poorly coloured specimen.
The second principle: always buy certified. A reputable laboratory report confirms species, origin, and treatment status — protecting your investment and giving you confidence in what you own.
