Sapphires are most commonly assumed to be blue but actually probably have the most versatile colour range of all the stones. They occur in the whole rainbow, we think. The third hardest mineral after diamond they rate a 9 on the Mohs scale making them so perfect for jewellery, as they are so hard to break. But don't they know it, they are get pretty pricey pretty quick. One way to tell a sapphire, is by looking for colour banding. This is the stripes of colour that your'll see through the stone, sometimes with the naked eye but probably under a jewellers loop (the little magnifying doodah that you see us looking through). 

Fun fact: Tessa's favourite stone she's ever seen was a greyish lilac sapphire in an unusual scissor emerald-cut. It was huge, now sold, and gone forever. But she remembers her fondly. 

Colours: Pretty much all colours, but most commonly blue. 

Mohs scale: 9

Crystal Formation: Trigonal

Country of Origin: Australia, Cambodia, Cameroon, China, Colombia, Ethiopia, India, Kenya, Laos, Madagascar, Malawi, Mozambique, Burma, Nigeria, Rwanda, Sri Lanka, Tanzania, Thailand, United States and Vietnam.