Spinel is probably a lesser known stone but, we think, kinda under rated. We love its cubic crystal formation, they are really interesting shapes. The hot pinks and reds of this stone are stunning and a great alternative to garnets or rubies, although not necessarily less expensive. Black spinel is also a favourite, it's harder than onyx so facets really nicely with a sharp polished edge and the crystals grow bigger than black diamonds so sometimes a perfect alternative to those too. 

Fun fact: The Black Prince's Ruby in the Imperial State Crown is actually a red spinel.

Colours: Red, pink, blue, green, brown or black.

Mohs scale: 8

Crystal Formation: Isometric system

Countries of origin: Sri Lanka, Afghanistan, Tajikstan, Burma, Vietnam, Tanzania, Kenya and Madagascar.