The Rare Beauties Collection, from £700, showcases unusual rocks like Tanzanite, which is teamed with diamonds to bring out the beautiful array of ultramarine blues and violets, with flashes of pinks and reds in-between. Discovered in 1960, it is found in only one location on earth.

Kunzite is another eye-catching stone used in the collection - it is phosphorescent, causing it to glow in the dark after exposure to daylight and is very new to the market.  Make a bold statement with this gorgeous 'Triumphant' ring - a cool £15,000 - and made from Tanzanite, diamonds and platinum.