Which metal is noted for being lightweight, strong, and hypoallergenic, despite being costly to manufacture?

Titanium is recognized for its outstanding combination of properties, making it particularly well-suited for various applications, including eyeglass frames. One of the key characteristics of titanium is its lightweight nature, which provides comfort for the wearer without sacrificing durability. Despite being strong and resistant to corrosion, titanium is also hypoallergenic, which makes it an ideal choice for individuals with sensitivities to certain metals.

While it may have a higher manufacturing cost compared to other metals, its long-lasting and robust quality often justifies the expense in eyewear. This unique blend of attributes—lightweight, strength, and hypoallergenic properties—makes titanium a preferred material in the optical field. Other metals like Monel, stainless steel, and copper do not offer the same combination of benefits, particularly in terms of hypoallergenic properties or weight, which is why they are not considered the best answers in this context.