NECKLACES arranged by most recent to earliest worn from its FIRST appearance starting Engagement Day.
DIAMOND AND RED STONE FRINGE NECKLACE


The fringe elements only go around the front of the necklace very much like a bib.
This necklace has a matching bracelet.

Dec 19, 2011 The Sun Military Awards: http://justjared.buzznet.com/2011/12/19/prince-william-duchess-kate-the-sun-military-awards/
GOLD DISK NECKLACE
This is a different than the one worn Oct. 2010 and has three layers: a large hammered gold disk, medium-size polished gold disk and a gold ring.

Jun 30, 2011 Youth Reception in Rideau Hall, Ottawa: http://www.zimbio.com/pictures/0PkguXh2rHY/Prince+William+Kate+Middleton+Youth+Reception/wSSqKG6q7Ms/Kate+Middleton
DIAMOND CROSS PENDANT
Catherine wears a diamond cross pendant at The Order of the Garter Service


June 13, 2011 The Order of the Garter Service: http://www.zimbio.com/pictures/gtm0UdnUjRD/Royals+Attend+Order+Garter+Service/zVgM_SmI2q6/Kate+Middleton
She has had this diamond cross for many years. I first spotted it at the wedding of Hugh van Cutsem and Lady Rose Astor June 4, 2005.

SHELL NECKLACE
Fresh and tanned from her honeymoon, Catherine wore what looks like a shell necklace when she met the Obamas on May 24, 2011.

May 24, 2011: http://www.zimbio.com/pictures/cvjpo9xhDJe/Barack+MIchelle+Obama+Meet+Prince+William/Zie8CZfAstZ/Kate+Middleton
TIFFANY AND CO. SAPPHIRE BEZEL AND DIAMOND STATION NECKLACE
Necklace worn on Catherine and Prince William's official engagement announcement, Nov. 16, 2010. The oval cabochon sapphire is set in yellow gold bezel. Two bezel-set diamonds on either side of the sapphire separated a chain. This necklace has matching earrings.

Nov 16, 2010 Meeting the press at Clarence House: http://www.zimbio.com/pictures/2Kx_DlgccBd/Clarence+House+Announce+Engagement+Prince/Ze5n8NQ2-qY/Kate+Middleton
This necklace and matching earrings were first seen at the wedding of Lady Rose Windsor and George Gilman July 19, 2008.

Thanks to the facebook page of What Kate Wore, the necklace has been as coming from Tiffany & Co. by Elsa Peretti. A similar necklace can be seen here: http://www.worthpoint.com/worthopedia/tiffany-co-18k-gold-diamond-sapphire-necklace
ASPREY 167 BUTTON DIAMOND PAVE PENDANT IN 18K WHITE GOLD
This disk pendant was worn Oct 23, 2010 before their engagement. I thought I'd include it here since the earrings worn at this event were worn on January 8, 2010 at another wedding.

Oct 23, 2010 Harry Meade and Rosie Bradford Wedding:

It looks like this disk has pave-set diamonds and a stone in the middle. It reminds me of a round evil-eye pendant. There are letters engraved on the side of the disk. I can make out the word 'BOND'.
July 1, 2011 Canada Day, Ottawa: http://www.ibtimes.com/articles/172977/20110701/kate-middleton-stunning-celebrates-canada-day-144th-reiss-dress-ottawa-fashionista-sylvia-fletcher-f.htm
July 22, 2011 Wedding Dress Exhibition at Buckingham Palace: http://www.zimbio.com/pictures/9CHrIUI0yUD/Buckingham+Palace+State+Rooms+Summer+Opening/kTvJpmoye9Z/Kate+Middleton
The earliest sighting of this pendant was June 3, 2006 at the Boodles Boxing Ball: http://socialitelife.com/enlargedimage?back_to=/kate-middleton-will-not-obey-prince-william-04-2011/boodles-boxing-ball&postid=5893862 and http://socialitelife.com/enlargedimage?back_to=/kate-middleton-will-not-obey-prince-william-04-2011/boodles-boxing-ball-2&postid=5893871
Thanks to What Kate Wore for identifying that this necklace is from Asprey's.
Here are pictures of the pendant in 18K yellow gold from Luxury Bazaar:


Dimensions: Length of the necklace is 18 inches, width of the pendant 15 mm and
drop of the pendant is 20 mm
Description: Cute Asprey 18K yellow gold and diamond button necklace and
pendant, stamped 167 New Bond Street London. Total diamond weight is 0.40 ct.
The circumference of the disk is engraved with LONDON - 167 NEW BOND STREET
The matching earrings in 18K white gold also shows the engraving.

