I heard back from S.J.Phillips and her necklaces are Amythest, Aquamarine and Topaz 18th century collets mounted in gold.
I did not have the courage to ask! But a similar item on the website gives a price estimate of between 5 and 10 thousand Pounds, with others costing much more. Check out the website to get an idea of what they look like. If you enquire, they will be happy to supply prices--let me know!Did they happen to say how much they are (dare I ask)?