Strength measured how? Diamonds can shatter and break, it's only hard to scratch them. Metals won't shatter so easily, but they may be scratched.
Rockwell Hardness is MY guess......nothing I noticed in the article points to anything else.
I believe the nanotubes are flexible, not sure how tough they are directionally, but they must have the ability to withstand a lot of vertical stress that would be neccessary for a space elevator-type application.
"Strength measured how? Diamonds can shatter and break, it's only hard to scratch them. Metals won't shatter so easily, but they may be scratched."
Yeah, and you can scratch on the break but that is only in pool.