I would like to buy a pair of pure titanium eyeglasses from the online stores as they can provide much cheaper price than retail stores. But how do I know if a eyeglasses frame is pure titanium? And what is the estimated price for the pure titanium eyeglasses online?

Hi, I just want to buy a pair of discount titanium frame. And I want to know how to confirm the pure index of the titanium frame too! i just went to the high street optical shop, the price of the titanium which is not 100% pure titanium is expensive too. I think I could buy one online with lower price. Who can tell us which online optical shop is best? and where can I get discount titanium glasses?