Talc
Coal, as an organic sedimentary rock, is not determined to have a hardness on the Mohs scale of mineral hardness.
The scale used to measure the hardness of a rock is called the Mohs scale. It ranges from 1 (softest) to 10 (hardest) with each level representing a different mineral's ability to scratch another.
Breccia does not have a specific hardness on the Mohs scale because it is a type of rock composed of different minerals. The hardness of breccia would vary depending on the hardness of the minerals present in its composition.
it is 6 1/2 in the mohs hardness scale
Talc (1 on the Mohs Hardness Scale) can be scratched by a fingernail.
Galena is listed at 2.5 on the Mohs scale of mineral hardness.
Talc is the mineral with a hardness of 1 on the Mohs scale.
Chalcopyrite has a hardness of 3.5 to 4 on the Mohs scale.
The Mohs standard hardness scale that was developed by Friedrich Mohs (1773 - 1839).
Bauxite, a rock and the main ore of aluminum, does not have a number on the Mohs scale of relative mineral hardness because it is not a mineral, but a combination of minerals.
Talc.
Relative hardness is the property of minerals that uses the Mohs scale for classification.