Gemstone Directory
The professional gemstone encyclopedia
Properties, pricing factors, care instructions, and insider buying tips for every major gemstone — written by trade professionals.
Precious Gemstones
The traditional 'big four' — diamond, ruby, sapphire, and emerald — plus other stones that command precious-level prices.
Diamond
10 MohsThe hardest natural substance and the benchmark of the gemstone world.
Read guideEmerald
7.5–8 MohsThe green jewel of royalty, prized for its saturated color above all else.
Read guideRuby
9 MohsThe king of colored gemstones, valued for its vivid red brilliance.
Read guideSapphire
9 MohsCorundum in every color except red — the most versatile precious stone.
Read guideSemi-Precious Gemstones
Remarkable stones valued for their unique optical properties, color range, and character. Many rival precious stones in beauty and collectibility.
Alexandrite
8.5 MohsThe chameleon gem — green in daylight, red under incandescent light.
Read guideAmethyst
7 MohsThe most popular purple gemstone — once valued alongside diamonds.
Read guideAquamarine
7.5–8 MohsThe sea-blue beryl — elegant, eye-clean, and universally flattering.
Read guideGarnet
6.5–7.5 MohsA family of gems spanning every color — not just the deep reds.
Read guideMorganite
7.5–8 MohsThe pink beryl that became the alternative engagement ring stone.
Read guideOpal
5.5–6.5 MohsNature's kaleidoscope — a play of spectral fire locked in hydrated silica.
Read guidePeridot
6.5–7 MohsThe extraterrestrial gem — found in meteorites and volcanic basalt.
Read guideSpinel
8 MohsThe great imposter — historically mistaken for ruby and sapphire, now prized in its own right.
Read guideTanzanite
6–6.5 MohsFound in only one place on earth — a violet-blue stone rarer than diamond.
Read guideTopaz
8 MohsFrom imperial orange to electric blue — a versatile and durable gem.
Read guideTourmaline
7–7.5 MohsThe rainbow gem — no other mineral occurs in as many colors.
Read guideExplore more resources
Dive deeper into jewelry terminology or compare gemstones and materials side by side.