Mohs scale of mineral hardness
A &lt;111&gt; surface (normal to the largest diagonal of a cube) of pure diamond has a hardness value of 167±6 GPa when scratched with a nanodiamond tip, while the nanodiamond sample itself has a value of 310 GPa when tested with a nanodiamond tip. However, the test only works properly with a tip made of harder material than the sample being tested due to cracking. This means that the true value for nanodiamond is likely lower than 310 GPa. Due to its hardness, a hyperdiamond could possibly exceed 10 on the Mohs scale of mineral hardness.