Which one of these is the hardest to scratch?

Sandstone
Soapstone
Chert
Talc
Granite
Shale

Well the top three hardest are Diamond, Sapphire and Ruby, and an easy way to remember is: red-white & blue stones! The hardness of a gemstone is measured on its place on Mohs scale of hardness. 10 on Mohs scale being the hardest known naturally occurring substance– and the honor goes to the diamond

Although the hardest natural stone on the planet is a diamond that is rated ten on the Mohs scale, granite is known as the most durable and hardest natural stone that is used in construction material and is measured six on Mohs scale.

The hardest mineral commonly found in granite is quartz, which is normally a somewhat translucent, white to grey colored mineral.

(so from your options granite is the hardest to scratch )

hope it helps you

:)