What factors determine the value of a coloured gemstone? A big blue sapphire is a very valuable gem indeed. These crystals are very rare and rarity adds value. If the environment in which the crystal started growing in the earth remains stable, it has the potential to develop into a large, clean and vibrant gem. Read more: Discover the Storytelling Powers of Master Gem Carvers If it contains iron and titanium, it can appear blue - the sapphire. If it contains chromium, it can appear red. These impurities have the potential to change the crystal’s colour. So why does it command such prices when it is placed in jewellery? When the corundum crystal grows in the earth, it may let in chemical impurities. In fact, it is commonly used as an abrasive, think sandpaper or emery boards. Sapphire is a variety of the mineral corundum – a fairly abundant material composed of aluminium oxide. What makes Kashmir sapphires so special? What about the padparadscha? What role do treatments play in value? Here, Gem-A tutor, Beth West FGA DGA EG offers a beginner’s guide to sapphire value.

Cashmere sapphires