Diamonds are not found in soil. They are formed deep within the Earth's mantle under intense heat and pressure.

While diamonds can be found in kimberlite and lamproite pipes, these are not technically soils. They are volcanic rock formations that bring diamonds from the mantle to the surface.

Here's a breakdown:

* Kimberlite: A dark, fine-grained igneous rock that is the primary source of diamonds. It forms when magma from the mantle erupts rapidly to the surface.

* Lamproite: Another igneous rock type that can contain diamonds. It is similar to kimberlite but has a higher potassium content.

So, while diamonds are associated with these rocks, they are not found directly in soil. They are mined from the rocks themselves.