Pink tourmaline white topaz pendant necklace in platinum over 925 silver

This is a gently pre owned necklace from an estate purchase, in excellent condition showing little to  no signs of use.  Pink stone tests and views as tourmaline. White stones test as topaz. Set in what appears to be platinum plated over sterling silver. Pink gemstone “flutters” or “dances” suspended from the middle of a double halo setting. Chain measures 18 inches. Purity stamp on chain is 925. Purity stamps on pendant are 925 on the bale, but on the back of the pendant , also has 50 PCT 002357 which I believe means it’s a platinum plate or platinum vermeil over sterling silver. Bale is engraved 925 DK China. Reasonable offers considered