I don’t know whathappened to plain old diamonds but a quick look at the wares of our most fashionable jewellers will reveal that sweety-coloured stones are the current fancy. And small is not in vogue. These stones — deep pink rubelites, pink tourmalines, lavender amethysts, grass-green beryls and peridots, pink sapphires and Tsavorite garnets — are fashioned into great pieces of jewellery that are not for shy, retiring types. But it’s the rings that have caught my eye: they’re getting bigger and bigger.

I’m not sure whether Solange Azagury-Partridge quite knew what she was starting when she launched her sock-it-to-you cocktail rings a few years ago now. What seems to have happened is that women earning salaries who have been buying discreet bits of jewellery for themselves, have started to buy rings, having tired of waiting for an engagement ring.

Some of the offerings from the mainline jewellers at present are irresistible. At Cartier there’s a delectable new collection of jewellery called Délices de Cartier, pictured above, all pretty colours. But it’s the rings that make the most impact. Even the smaller one, made from white gold and an asymmetrical collection of a pink ruby, yellow beryl, mandarin garnet and pink tourmaline packs a punch for the £3,025 it costs.

At Asprey there’s a Maxi Chaos ring with a combination of blue topaz, pink tourmaline, peridot, amethyst and citrine, set into 18-carat white gold; prices from £1,700 (depending on the size). At Tiffany, Paloma Picasso’s sugar-stack rings come in single singing colours — yellow, blue, green, purple, claret, bright green cabochon cut stones, but from £675 for the smaller size (7mm x 7mm) and from £1,076 for the larger (12mm by 12mm) — all depending on the stone. Lots of drama for the money.

If you’re so old-fashioned as to want diamonds, rough, unpolished and uncut is how those in the know are buying them. The rough ones from the Golconda mine in India used to be much fancied by maharajahs and are now being used by mainstream companies.

De Beers, for instance, has had success with its Talisman Collection, which is based on rough diamonds in muted sandy colours. Its Nebula ring, for instance, circles of white gold inset with a mixture of rough and polished diamonds (£2,600), is a stunner.

Pippa Small does much the same with rock crystal: she treats it rough. Her great organic piece of rock crystal is embedded in 22-carat gold for £2,500. She is opening her own shop in a fortnight’s time at 11 Colville Mews, Notting Hill, London W11, where there’ll always be a large selection on sale.

If your tastes run to more designery pieces, take a look at the work of Kelvin J. Birk. He takes precious stones — amethysts, rubies, emeralds, sapphires — and crushes them and then reconstructs the smashed stones on to precious-metal structures. He makes to order: prices from £180. Find him at Cockpit Studios, Cockpit Yard, Northington Street, London WC1 (020-7691 8080) and kelvinbirk.com.

But if you fancy a great knockout ring and can’t pay such prices, plenty of jewellers offer lots of impact for smaller sums. Philippe Ferrandis makes jewellery under his own name, as well as a collection for Daniel Swarovski. Many of his pieces are well priced: pretty rings made from crystal cost £80.

The website reglisse.co.uk is selling his wares but if you want to touch and feel, you can see the wares at 280 Fulham Road, Chelsea, London SW10 (0845 0942120, appointment only). And check out lolarose.com for very inexpensive rings that make a big statement.

Times recommends

• It is possible to look stylish while pregnant
• Britain’s tot models
• Who and what benefits from the heat wave?