Titanium

Nowadays, eyeglass frames are available in a huge variety of styles, sizes, and materials. Titanium comes out of the ground. In rocks. It is popular because of a very high strength-to-weight ratio. For example, it might take a pound of steel to hold up king kong, but it only takes 1/2 a pound of titanium to do the same thing. While heavier than aluminum, pound-for-pound, titanium is twice as strong.
The benefit for using titanium in glasses frames now seems obvious. Titanium will result in eyeglasses frames that are equally as strong as steel glasses frames yet are only half the weight. Titanium glasses frames is very expensive, A final note is that titanium is often alloyed, or combined, with other metals such as nickel. Some titanium glasses frames are 100% and some are alloys. Unfortunately, the online eyeglasses retailers don’t seem to be disclosing this information. Titanium eyeglass frames are lightweight, durable and hypoallergenic. The perfect frames for active lifestyles or heavy prescriptions.
Stainless steel is an alloy of steel and chromium; but sometimes may also contain another element. In general, stainless steel contains 10 to 30 percent chromium, which imparts it an excellent resistance to corrosion, abrasion and heat. Lightweight, low toxicity and strength are the other noteworthy qualities of stainless steel. Those steels containing only 10.5% to 27% chromium are said to be nickel-free and thus hypoallergenic. Due to lack of marketing efforts and availability, stainless steel does not enjoy the same popularity as titanium, despite its qualities and reasonable cost. Titanium eyewear can be produced in a variety of colors for a clean, modern look with a hint of color. And they're hypoallergenic. Some titanium frames are made from an alloy that is a combination of titanium and other metals, such as nickel or copper. In general, titanium alloy frames cost less than 100 percent titanium frames.
It's also difficult and expensive to extract and refine this abundant material. Titanium provides a durable and long lasting material that is corrosion resistant... a good choice for someone who intends on keeping their frames for an extended period.