JEWELS, artworks and books collected by one of the UK's leading authors of romantic and Arthurian novels are to be sold at auction in Edinburgh in the next two months.

Lady Mary Stewart, who died aged 97 in May this year, lived for many years in Edinburgh and at a house near Loch Awe in Argyll.

A native of the north-east of England, Lady Mary moved to Scotland after marrying Frederick Stewart, a lecturer in geology, and after settling in Scotland's capital she began her successful writing career.

Her most famous novels are three books she set in the time of King Arthur - The Crystal Cave (1970), The Hollow Hills (1973) and The Last Enchantment (1979).

Now items from her estate are to be sold by auctioneers Lyon & Turnbull in three separate sales.

These include a Cartier brooch, designed as a crescent moon and commissioned by Lady Mary after the publication of her novel Moon Spinners.

It has been valued at £20,000 to £30,000.

There is also a Cartier diamond ring made out of the spare diamonds left over from the commission of the brooch, which is valued at £5,000 to £7,000.

Other jewellery being sold comprises a necklace made from opal beads and rock crystal, an antique opal-and-diamond crescent brooch, an antique ruby/garnet-and-diamond crescent brooch and an oval cluster ring.

Lady Mary collected many Asian works of art in the 1960s and 1970s, and some of these are also for sale, including a Jade Celadon and dark brown Chimera from the Ming Dynasty dating from 1600 to 1640, priced at between £8,000 and £12,000.

From her library there are a number of books, which include a first edition Darwin's Origin of Species valued at £15,000 to £25,000, and there is also a collection of works illustrated by Arthur Rackham, and other illustrated and children's books.

Jennifer Ogden, niece of Lady Mary, who lived with the writer in her final years, said the writer, who had no children, had a "great eye and a wicked sense of humour".

She said: "There are a lot of memories here and as a family we had to decide what to keep, but we could not keep everything.

"She loved beautiful things.

"The jewellery, she would buy herself - she would buy a piece every time she produced a new book, and she loved them dearly."

She added: "She always said she wrote for the love of it and this collection of items in the sale reflect her love of beautiful things.

"It was a very difficult decision to sell the collection, and we hope that every single item goes to someone who will really treasure it."

She was born Mary Rainbow on September 17, 1916, in Sunderland and graduated with a double first in English and French from the University of Durham, where she also lectured.

It was in Durham that she met and married her husband, Frederick Stewart, a Scot.

They married in 1945, only three months after they met at a VE Day dance.

Mary, in her own words, was a "born storyteller" and had been writing stories since the age of three.

The first novel she submitted to the publishers Hodder & Stoughton, publishers for all her works, Madam, Will You Talk? was an immediate success.

Her Arthurian novels came from her interest in Roman-British history.

The Crystal Cave was a number one bestseller for weeks and her Merlin books were the ones of which she was most proud.

In a rare interview about her Arthurian trilogy, she once said: "Don't forget what a dreadful life those medieval women must have led, shut up in those ghastly castles while the men were away having fun. Nothing to do but your embroidery, and play at ball in the garden.''

Lady Mary also wrote a small number of children's books, including A Walk in Wolf Wood

Lady Mary's husband, Sir Frederick, who was knighted in 1974, died in 2001.

The items will be sold at Lyon & Turnbull's specialist sales.

The first will be Lyon &Turnbull's Fine Sale of Asian Works of Art on December 2, which will be followed on December 10 by the Sale of Select Jewellery and Watches.

On January 10 there will be a Sale of Rare Books and Manuscripts.