Now that it came up, I'd like to give a quick nerdy talk of material physics: strength, toughness, and hardness. And it is easier to think of three properties in the extreme, each is represented by a strip of rope, a strip of tire rubber, and an unrelated piece of diamond.
Strength: ability for material to withstand load (compress, pull-tension, slide-shear). A strip of rope can maintain its shape and length under a load where the strip of tire would deform and extends.
Toughness: ability for material to take on energy (instead of load) before breaking. A strip of tire would extend far under a load which would otherwise snap the strip of rope.
Hardness: ability for material to retain its molecular structure consistency under force/load. Scratching on both rope and tire would leave rope/tire pieces/particles under your nail, but scratching on a diamond wouldn't.