Slate is a rock, so you won't find it listed on the Mohs Scale, because that scale of hardness applies to minerals. I'll go out on a limb though, and suggest that slate is probably around 2 to 3 or so, but this will be variable, depending on the quality of the slate, and degree of weathering, etc.
The hardness of Limonite is 4 t0 5.5 on the mohs hardness scale.
It is about 2.5 in the Mohs Hardness Scale.
The fourth mineral on Mohs' Scale of Hardness is fluorite. It has a hardness of 4 on the scale.
The Mohs Scale of Hardness determines the hardness of minerals by scratching them with commonly found objects. The minerals are assigned a number which corresponds to their hardness; higher numbers indicate higher hardness.
The hardness is 6 on the MOHS scale
Slate, being a metamorphic rock, would not have a hardness listing on the Mohs scale of mineral hardness.
Diatomite has a hardness of around 5.5 on the Mohs scale of hardness.
It's called the Ore
The hardness of Limonite is 4 t0 5.5 on the mohs hardness scale.
Azurite has a hardness of 3.5 to 4 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
Nickel has a hardness of 4 on the Mohs scale.
The hardness is 3-4 on Mohs scale.
Dolomite has a hardness of 3.5-4 on the Mohs scale of hardness.
The Mohs scale is used to determine the relative hardness of minerals.
Aluminum Oxide is roughly 8.5 - 9.0 on the hardness scale.
This scale was proposed by the Austrian geologist Friderich Mohs.