Pear Shape Amethyst Ring sz. 7-3/4

Set in sterling silver, marked Thailand 925 is this huge Cushion Cut Pear Shape Amethyst ring. Size 7-3/4. The amethyst measures approx. 12 x 16 mm. It is cushion cut, deep purple in color. It is set in sterling silver. I bought this from JTV. The amethyst is surrounded by 25 prong set stones that are probably white zircon. JTV commonly sets white zircon as accent stones. I am not sure about them. This ring has some signs of wear consistent with use. It is a large, bold statement piece. I bought it from JTV but I didn't keep the paperwork. Questions? Please ask.