The mineral particles found in the layers of a soil, including topsoil and subsoil, were originally weathered from parent rock.

Here's how it works:

* Weathering: This is the process where rocks are broken down into smaller pieces by forces like wind, rain, ice, and temperature changes.

* Parent Rock: The original, solid rock from which the soil minerals are derived.

* Soil Formation: Over time, the weathered rock fragments (along with organic matter from decaying plants and animals) form different layers (horizons) in the soil.

So, the minerals in your topsoil and subsoil are essentially the broken-down remains of the rocks that existed before the soil developed.