Gemstones
Complete List of Gemstones A to Z
Precious and semi-precious gems from Alexandrite to Zircon, with hardness and key buying notes.
Precious gemstones
Diamond (hardness 10), Ruby (9), Sapphire (9), Emerald (7.5–8). These four have traditionally been considered the 'big four' of the gem world.
Fine coloured gems
Alexandrite, Aquamarine, Amethyst, Citrine, Garnet, Morganite, Opal, Paraíba Tourmaline, Peridot, Spinel, Tanzanite, Topaz, Tourmaline, Tsavorite, Turquoise and Zircon.
Organic gems
Pearl, Coral, Amber and Jet are created by living organisms. They are softer and need more careful wear and storage.
Hardness and everyday wear
The Mohs scale ranks scratch resistance from 1 to 10. For rings worn daily choose gems of 7.5 or higher; softer stones like opal (5.5–6.5) and turquoise (5–6) suit earrings and pendants.
Verification tools & references
Every Riakoob piece arrives certified, insured and covered by our 12-month value promise.
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