Our coloured gems are all carefully selected for their deep rich colours



Sapphire is part of the mineral family named Corundum. It is a hardwearing gemstone second to diamonds on the gem hardness scale. We provide sapphires in a whole spectrum of colours except red; red corundum is called Ruby.

Sapphires larger than two carat are very rare and therefore very valuable. Gem dealers often heat sapphire to enhance colour, this is an accepted part of the gem trade and the treatment is permanent. This being said, we also supply Sapphire which is not heat treated. This can only be guaranteed if it comes with a certificate stating there are no signs of heat treatment. These rare stones come at a premium.

We obtain the majority of our Sapphire from Sri-Lanka (Ceylon) and Madagascar. However, we work with you to find that perfect colour. For example, darker sapphire comes from Thailand and Australia.



Ruby, like Sapphire, is a variety of the mineral Corundum. It is also a durable gemstone well suited for the demands we place upon jewellery. Top quality Rubies are incredibly rare whereby the bigger sizes are frequently prized above all gemstones, including Diamonds. Rubies over two carats with true red colour are regarded as more valuable above those that are darker with hints of purple.



Top quality Emerald can be as rare as fine diamond. The most attractive emerald in relation to colour is in the middle of the colour range between dark and light green – an intense grassy colour fairly free of inclusions. Expert’s say that a dark velvety green is the most valuable however, with coloured gem, we say beauty is in the eye of the beholder. Gemstone dealers oil the majority of emerald which helps to fill the cracks which the stone is prone to. This process can improve the colour and clarity but is considered a universal and one must assume this has taken place. Whilst jewellers accept oiling in the gemstone industry, we advise our clients to avoid glass filled emeralds that have been through less natural processes.



Tanzanite was found and named in Tanzania in 1967. The colours are often a purple hue of blue, lilac blue, or deep violet; you can also see them in green and brown. The production of the deep blue/purple colour is heat treated and is an accepted part of the fine gem trade. Tanzanite is a delicate stone which can fracture therefore jewellers avoid ultrasonic cleaning. We advise our customers to be conscious when wearing it in a ring. However, when you look after this beautiful stone correctly, it is still very suitable for fine jewellery.



The most precious of the semi precious gemstone. Jewellers have used Aquamarine Jewellery for thousands of years dating back to ancient Egypt. Sailors also used it as a lucky gemstone for sea travel. It is part of the Beryl family of gemstone, which emerald also is part of. We advise our clients to care for Aquamarine in a similar way to emerald and treated as a delicate stone. It is not as robust as diamond, ruby or sapphire. Regardless of this fact, it is a stunning mineral suitable for jewellery if cared for.



Coloured gemstone is not as hard as diamond – please call 01273 978157 us or email to ask advice on cleaning coloured gem.

At Kellerwood we often procure consignments of coloured gem, upon request, to find you that perfect rare coloured gem. We look forward to working with such rare minerals so please do not hesitate to get in touch and discuss how we can help to commission.