Traces of vanadium tint sapphires blue, whereas traces of iron create yellowish-green colours. In rubies, traces of chromium absorb yellow-green light, giving them a red hue. In many coloured gems, the brilliant hue, which makes them sought after, is the result of impurities.ДЇor example, rubies and sapphires are derived from the same mineral, corundum. Like all gemstones, coloured gems are minerals prized for their beauty and rarity, often in crystalline structures and sometimes organic in origin, such as amber and jet. But as larger companies such as Gemfields provide more consistent supply, confidence increases in the sector. The artisanal nature of the market can deter designers from using coloured gemstones in their ranges, fearing inconsistencies in supply common to small mines. The fragmented market leaves few big companies to champion and actively market coloured gemstones. Historically, De Beers dominated the diamond sector, and a good deal of the success of diamonds can be traced back to its famous 1947 marketing campaign, вЂA diamond is foreverвЂ™ which popularised diamond engagement rings (in 1940 just 10% of brides in the United States received a diamond engagement ring).Д«y comparison, small-scale artisanal mining makes up 70вЂ“80% of coloured gemstone production. In fact, contrary to common belief, data from SothebyвЂ™s and ChristieвЂ™s auctions show per-carat prices for emeralds and rubies can exceed white diamonds.

That is not to say diamonds are more expensive than coloured gemstones.

вЂDiamonds may have dominated the global gemstone market for many years, but we believe coloured gemstones will be the key growth area over the next decade.вЂ™ Alison Turner, Edison mining analyst How large is the coloured gemstone market?Д¬oloured gemstones do not support trade on the same scale as diamonds, with US$16bn in rough diamonds produced yearly worldwide versus US$2вЂ“3bn in rough gemstones, excluding jade.

Largest ruby mine in the world