This year Maison Martin Margiela has revived its Ligne 12 fine jewellery line after a five-year hiatus. The Pompadour collection plays with the concept of the family heirloom. Think a Ceylon sapphire, in an old-fashioned diamond setting that has been cloven in half for an edgy take on inheritance jewels. Similarly speaking, the witty Héritage collection is made up of 'non-engagement' rings of bisected white diamonds - fittingly sourced in Antwerp - set at each end of a gap in a white gold band.

Meanwhile, investment banker turned innovative jewellery designer William Welstead also likes the idea of imperfect diamonds. 'Sliced stones are something of a trend,' he admits, 'but I like to think I was one of the earlier ones to admire the aspect of different cuts.' Destined to be cut and polished horizontally for his pear-shaped pendants, Welstead pulls out a handful of Macle diamonds (a flat, triangular crystal which has turned in on itself during formation). The imperfections are part of the attraction: 'There is a joy in diamonds - what really matters is whether the stone has charm or not.'

He also uses parab cuts, which are flat-bottomed, with triangular facets forming a pointed crown. They were highly prized by Mughal emperors in 16th century India. Welstead turns them into Indian wedding jewellery, setting them in white gold: 'I love a stone with a low profile - flat rose cut diamonds are a little more informal, more playful.'

Then there are the unorthodox pearl forms of Melanie Georgacopoulos, whose work was picked by Zaha Hadid for her showcase of personal highlights from this year's Goldsmiths' Fair in London, the UK's most prestigious exhibition of fine jewellery and contemporary silverware. She drills and facets pearls, or strings halved pearls together, either leaving them sliced open or lining them with yellow gold for Japanese jeweller Tasaki.

It was curiosity that led her to this approach, to cut into them, she says. 'I wanted to know what pearls looked like on the inside. I was so impressed by what I discovered that I decided to make an entire collection using them.' Her pearls are self-consciously modern. 'It's important to be daring, to try new techniques and change people's perceptions. We should make jewels that represent contemporary times.'

TAGS: JEWELLERY, MAISON MARGIELA