The pH scale does not measure hardness it measures the acidity or otherwise of substances
u can chek the hardness by pH scale...lolz
The hardness of Limonite is 4 t0 5.5 on the mohs hardness scale.
flint is a type of quartz, so it has a hardness of about 7 on the mohs scale of hardness
Diatomite has a hardness of around 5.5 on the Mohs scale of hardness.
The Mohs scale is used to determine the relative hardness of minerals.
Dolomite has a hardness of 3.5-4 on the Mohs scale of hardness.
It's called the Ore
Pumice has a hardness of about 6 on the Mohs scale of mineral hardness.
Azurite has a hardness of 3.5 to 4 on the Mohs hardness scale.
the hardness of Topaz is 8 on moes hardness scale
The fourth mineral on Mohs' Scale of Hardness is fluorite. It has a hardness of 4 on the scale.
Aluminum Oxide is roughly 8.5 - 9.0 on the hardness scale.