A macadamia nut.
The hardest nut to crack is difficult to open because it has a very tough outer shell that requires a lot of force to break through. This shell is designed by nature to protect the seed inside from predators and the elements.
The answer is a Nutcracker
The nut with the hardest shell is the macadamia nut. It is difficult to crack because the edible part is stuck to the inside of the shell.
There is. The starter's on the right-hand side of the car. Look between the firewall and the fan shroud on that side, and you'll see a 17mm nut. That's the top nut holding the starter in, and you might need to clamp a pair of vise-grips to the head of the bolt to get the nut off. It is in possibly THE hardest place in the world to maneuver a pair of vise-grips into.
diamonds are the hardest
Diamonds are the hardest mineral and the agate is the secod hardest mineral.
A punch nut is not a locking nut
From what I hear, One is the hardest & Master of Puppets is second hardest.
Diamond is the hardest precious stone
the hardest i can think of is "What is the answer to this question?"
Expert is the hardest.