Do rocks/stones etc have much carbon in them?

Question

also does soil have much carbon in it?

Answer 1

darkguy,

The posting above is dead on.

Most rocks have very little carbon in them. But there is a class of minerals (and rocks based on them) called carbonates that have a significant carbon content. The limestone that Mike mentions is one of these. In addition, black shales have organic material in them and thus also have a significant carbon content.

Soils have even more carbon, because a key ingredient in soils is "humus", which is just decaying organic matter. So yes, most soils have a fairly high carbon content. Usually the blacker the soil, the more carbon it contains.

Answer 2

Depends on the rock. Limestone is Calcium Carbonate, so it has a fair percentage of the stuff. Granite does not.
Soils also depend on rock contents, but black or brown soils tend to have a lot of organic solids - compost - and that has a high percentage of carbon.