Medium-grained typically refers to the intermediate size of particles or crystals in a material. It falls between fine-grained (small particles) and coarse-grained (large particles). Materials with a medium grain size might exhibit a balance between strength and ductility.
Slate
The rock described is likely to be shale, which is a sedimentary rock composed of clay minerals. Shale is typically white to gray in color, medium soft in texture, and fine-grained.
Slate
Rock, soil, etc.
Sandstone is an example of a medium-grained clastic sedimentary rock. It is composed of sand-sized particles that are typically visible to the naked eye, giving it a medium-grained texture. Sandstone forms from the accumulation and cementation of sand grains.
Silt is the medium-sized soil particle that feels silky. It is a fine-grained soil that has a powdery and smooth texture when dry, and slippery and smooth texture when wet.
Sandstone is an example of a medium-grained clastic sedimentary rock. It is formed from the accumulation and cementation of sand-sized grains (0.06–2mm) of mineral, rock, and organic particles.
Coarse
I'm not too sure
In fine grained soil very fine particle are there which has got some chemical repulsion, these chemical repulsion does not allow particle to come closer due to which void ratio of fine grained soil is higher than coarse grained soil.
Medium-grained typically refers to the intermediate size of particles or crystals in a material. It falls between fine-grained (small particles) and coarse-grained (large particles). Materials with a medium grain size might exhibit a balance between strength and ductility.
Silt is a fine-grained fertile soil deposited by water.
sandstone
The list that orders rocks in increasing grain size and increasing grade of metamorphism is: shale (fine-grained) - slate (fine-grained) - phyllite (medium-grained) - schist (medium to coarse-grained) - gneiss (coarse-grained).
The falling head test is not suitable for coarse grained soils like gravel because the test requires a fine-grained soil that can create a seal at the base of the standpipe. Coarse grained soils like gravel do not form a tight seal, which can lead to inaccuracies in measuring the permeability of the soil sample. The test works best with fine-grained soils with low permeability.
Phyllite is an example of a fine-grained foliated metamorphic rock