Kraig Biocraft Laboratories Inc (KBLB)

[GTman1]

I was surprised to learn that glass fibers are a lot tougher than that, from 3.4 to 4.8 GPa.

I would be surprised to learn that too if I knew nothing about the science.

Fortunately, that's not true at all. Their is a huge difference between tensile strength and toughness.

If you need a tough fiber, use glass.

Please, nobody listen to the above quote. Especially if you're trying to build something that needs actual toughness. It would be dangerous to listen to such bad advice.