The £600k worth of jewelry that Kate Middleton has amassed since becoming a royal

She might have grown up in a solidly middle-class family, but only six years after marrying Prince William, the Duchess of Cambridge has quietly amassed a personal jewellery collection worthy of a princess.

Kate doesn't just have access to the Queen's priceless gems. Increasingly, she can pick accessories from her own high-end pieces.

The duchess's collection is hard to value precisely, given the unique nature of some of her jewels. 

The sapphire and diamond engagement ring that belonged to Princess Diana, for example, presented by William to his fiancee, would cost in the region of £300,000 if it were to be commissioned today.

But given its provenance the ring would fetch ten times that figure, or more, if it ever came up for auction – something the Royal Family would never countenance.

According to a new book, How To Dress Like A Princess: The Secrets Of Kate's Wardrobe, Kate's collection is worth £600,000.

But that doesn't include pieces such as the £150,000 diamond bracelet thought to be a gift from Prince Charles, or items given to Kate in her role as a member of the Royal Family – such as the diamond and platinum polar bear brooch presented during the royal tour of Canada.

This means the true value of her collection is likely to be closer to £1million.

The duchess, 35, has a distinctive style when it comes to her jewellery. She has 40 pairs of earrings, especially favouring those that dangle and show off her elegant neck.

She also has a preference for matching sets of earrings and necklaces, from the diamond parure (the name for a set of jewels designed to be worn together) her parents gave her on her marriage, to the £55,000 Cartier ring necklace and a pair of £35,700 matching earrings William is believed to have splashed out on for her.

The book's author, Claudia Joseph, says the duchess has a 'magpie-like eye' for jewellery.

'Although people tend to focus on the incredible gems and tiaras that she borrows from the Queen, most people will be amazed to see the extraordinary collection she has amassed since her marriage,' she adds.

'Not only did her husband give her Princess Diana's fabulous engagement ring, but he has given her birthday, Christmas and 'push presents' [to mark the births of Prince George and Princess Charlotte].'

Not bad for a girl who grew up in the Home Counties...

This article was first published on dailymail.co.nz and is reproduced here with permission.