An emerald and diamond pendant worth £55,000 has gone on sale at a Douglas jewellers.

The pendant is thought to be the most expensive item that jeweller Charles Alexander Limited in Strand Street has ever offered for sale.

It is emerald cut and is 20.45 carats. It measures 10 millimetres by 20 millimetres.

The pendant also has 22 diamonds of 4.20 carats and is set in 18 carat white gold.

The chain pictured in our photo is a diamond necklace which is sold separately by Charles Alexander Limited and would cost an additional £14,500.

Asked how long such an expensive item as the pendant would take to sell, Jean Allcock, who has worked at the jewellers for 31 years, said: ’It is difficult to say. Some items come in and go straight away and others can be in for a while. Hopefully it will sell quickly. You just can’t tell.

’We sold a sapphire and diamond bracelet the other day for £6,000.

’A few years ago we nearly had a diamond solitaire in worth £46,000 but we were pipped by Wilkins for it.

’Sometimes we get people who have done something wrong and want to buy their partner something to make up, but others just want to treat their partner.

’It’s nice to know there are still some romantic people in the world.’

Jean said that the shop buys their jewellery from a company in Hatton Garden, which is known as London’s jewellery quarter and is the centre of the UK diamond trade.

The word ’carat’ comes from the carob seed, the original unit of measure for diamond traders.

The carat is a unit of weight for precious stones and pearls.

Today, a carat is equal to exactly 0.2 grams, about the weight of a paper clip.

Emerald is a gemstone and a variety of the mineral beryl, colored green by trace amounts of chromium and sometimes vanadium.

Emerald is regarded as the traditional birthstone for May as well as the traditional gemstone for the astrological signs of Cancer.