Yes, I also read somewhere she no longer liked the turquoise clasp. I've tried/am trying to organize all my press photos and clippings of Diana and they are organized enough for the purposes of looking for this. So she wore the choker pretty frequently in 1982 and 1983 and then hardly at all in 1984. The only time I have a photo of her wearing it that year was on February 8 at the London Ritz at a party to unveil a new portrait of Charles. It still has the turquoise clasp. She was wearing a black velvet dress with polka dots. Color pictures of that evening can be found in many of the Trevor Hall books. Anyway the next time she wears the choker, or at least I'm pretty sure, is in Italy on April 28, 1985. She is wearing a burgundy silk stripe suit with matching hat, the clasp is now all pearls.
I have a theory. Around late 1984/early 1985 Diana brought her sapphire brooch from the Queen Mother to the jewelers- I think it was Garrards but I'm not sure, to be turned into the centerpiece of a pearl necklace (which was to become one of her most famous pieces) that she debuted at her brother's 21st birthday party on May 20. Perhaps no longer fond of the turquoise Diana brought her old choker along to be adjusted when she had her new one commissioned.
If anyone has anymore information I'd be really interested to hear it. I hope this helps Lille. I'm guessing 1990 would be the absolute latest she would have worn it. The latest picture I remember seeing her wear it in is from 1988.
Does anyone know if this was a wedding present or did she own the choker coming into the marriage?
She also wore it at Harry's christening in December 1984