Minecraft wiki entry for List_of_sediments, associated text: Clay – very fine sediments; found beneath bodies of water and common in aquifers
Coarse Dirt – dirt too rocky for plants to grow
Dirt – mixed-sized sediments that most plants can grow on; makes up the top layer of most land, above stone
Gravel – loose rock chips; found beneath bodies of water, on some shores & mountaintops, and in solitary underground pockets
Red Sand – loose mid-sized sediments; only found in mesas
Rooted Dirt – dirt overtaken by azalea roots
Sand – loose mid-sized sediments; found on shores and in deserts
Soul Sand – Nether material that can support netherwart, but slows creatures that step in it; burns greenish-blue
Soul Soil – Nether material that's visually similar to soul sand; burns greenish-blue