Coloured gemstones: buying guide
Sapphires, rubies, emeralds and popular gems: colour, origin, treatments and what drives value.
Quick answer
Coloured gemstones are valued mainly on colour, then clarity, cut, size, origin and treatment. Unheated stones and notable origins such as Burma, Kashmir or Colombia carry large premiums. A report from GIA, Gübelin, SSEF or AGL confirms origin and treatment.
Sapphires
Royal blue, Ceylon, Kashmir and fancy colours including padparadscha.
1–2ct heated blue: £400–£3,000; unheated fine stones much more
Rubies
Burmese 'pigeon blood', Mozambique and Thai rubies, and the glass-filling problem.
1ct heated good colour: £800–£5,000; unheated Burmese far higher
Emeralds
Colombian, Zambian and Brazilian emeralds, oiling and durability.
1ct minor-oil good colour: £1,000–£6,000
Pearls, opals, tanzanite and more
Popular gems at a glance: pearls, opals, tanzanite, aquamarine, amethyst, garnet and spinel.
From under £50 (amethyst) to thousands (fine black opal, natural pearls)
Buying or selling a gemstone?
Browse live adverts or list yours — private members get their first advert free.