This should give you a better understanding of mineral hardness:
http://www.answers.com/topic/mohs-scale-of-mineral-hardness
There is no such thing as a rock stone.
You need a diamond tipped bit to drill almost any rock.
Diamond is actually considered a mineral.
Diamond
In the Underground.
The stone carbonado is also known as black diamond.
A diamond object is usually called a diamond, but can also be called a rock, a stone, or simply bling.
Diamond or Gold
diamond because it is beautiful and the hardest type of rock
its not a stone you have to train it up near a rock in eterna forest
Only Diamond is as hard as diamond, and if their could be any gem stone as hard as diamond then it would definitely be Diamond.
The field test for diamond is 'extreme hardness'. If you believe that you've found a diamond stone, you can take it to a jeweler, who will apply a probe and verify your find as a diamond stone, or not.