Elvire arrived here first I see. Many Thanks.
Polymer clay is "Pâte polymère" but Fimo is also widely recognised as a word here!
I also had great problems with "rhinestone" - in the dictionary it says "diamant fantaisie". EBid have used "Strass" which I have heard used at auction sales describing vintage sparkly costume jewellery - the sort of stuff I would have called "paste" jewellery! Then there's Cubic Zirconium as Elvire has said. Maybe they are all the same thing?
I think perles de nacre coquillage is used for shell beads. The thin flat discs of "mother of pearl" are I think Perles plate de nacre.
I was stuck on gemstone too - the French/English dictionary says "gemme"???
Otherwise I think I agree with Elvire totally!!