Angelina Jolie will add glamour to the first ever major rock concert to be held in the City of London. On 22 February, City Rocks will be shake the Guildhall when the 600 year old building is transformed into the venue for 700 guests who will pay £600 a head to rock to Bryan Adams and Katie Melua. Though Angelina will not be present herself, the necklace she wore to the premiere of the film Salt will be auctioned with proceeds going to the Lord Mayor's appeal. This necklace, known as the Premiere Black Faceted Necklace, that has graced the neck of Angelina herself is made of 47 black spinels with a total weight of 74.35carats and is one of the "money can't buy" items under the hammer. The lucky bidder will also receive a note from the hand of Angelina herself. The Premiere Black Faceted Necklace is the first of the Style of Jolie jewellery collection ( read more about it here) created with LA jeweller Robert Procop. I went to meet Robert Procop last week when he was in London and got a little insight into this unique jeweller/star collaboration to launch later this year. The jewels all reflect Angelina's love of big coloured stones and a classic style of jewellery. According to Procop, who has known Angelina Jolie for 'many years', Angelina doesn't like big clusters of diamonds and prefers the cushion cut for coloured stones. Procop also told me that Angelina likes green and black and prefers the warmth of red gold over yellow gold. The style of the collection is very clean and the unadorned mounts highlight the beauty of the gems that shine out from the large, flat facets of the cushion cut. In the name of duty as your Jewellery Editor, I tried on the 27 carat emerald ring that Angelina wore, that according to Procop, she wore throughout filming in Bosnia as a first-time director. The very elegant and very large emerald ring didn't make it past the second joint on my ring finger. And unfortunately I don't think there is any way to whittle down finger girth so that ring is not to be mine by for the slim-fingered like Angelina. The strictly limited edition jewels in the Style of Jolie collection are special in more ways than one. Angelina's style is evident in the designs and in many cases has worn the jewels herself and signs each piece. But in my view, what makes these jewels even more beautiful is that fact that proceeds from the Style by Angelina jewels will go to her charity, The Education Partnership for Children of Conflict. Watch this space for more on these jewels that sparkle with celebrity goodwill.