Minecraft wiki entry for Soul_soil_farming, associated text: Soul soil can be used to produce the soul lighting variants, however it can also be done with soul sand. Soul soil can be used to produce blue fire and can be used for decoration, since it looks much smoother than soul sand. Soul soil can also allow you to run faster with Soul Speed, however unlike soul sand it will not produce upwards bubble columns and not use to grow nether wart, and that makes it ideal for producing speed tunnels. Soul soil otherwise can only be obtained via mining in soul sand valleys, however that biome is dangerous and uncommon.