Severine reminds me of the gentle lapping of waves on the shores around the coastline of Scandinavia, swirling into eddies around pebbles. I love the caressing of the strong gold bands around the stone, like a big hug on a cold windswept day by the sea.

Tourmaline comes from the Sinhalese term "turamali" meaning 'stone of mixed colours'. As part of an isomorphous series, in which a range of chemical compositions occur in many individual crystals, they can be found in almost every colour. From pinks, reds, forest greens and blues, colourless and transparent to multi-coloured and opaque shades, making it one of Cassandra's favourite gemstones. The birthstone for October, it appears to have an affinity with the autumnal time of year, its myriad of colours resembling autumn leaves, falling in a cacophony of colour. Turn to pink tourmalines for an emblem of friendship and unconditional love, or delight in vibrant green tourmaline to harmonise your internal energies.