soil is a biological construct and only occurs on Earth, the regolith on other planets will not support life without major amendments and modifications. there are orders of magnitude more types of minerals on earth that found in any sample from an extra terestrial source, and while not proven conclusivly there is strong evidence that the bulk of earthly minerals, have biological origins in there creation. what is not disputed is that the entire top 10km or so of our planet has biological components and biological modifications, 3 billion years will do.that to a world, the point bieng, is that extraterestrial regolith would be the substance to use in substantiating the premise under consideration, but was not.