Primary rock powder is obtained by grinding stones that are often millions of years old. Volcanic rock is usually used as the starting material because it contains a particularly high amount of minerals.
Rock powder contains almost no main nutrients and is therefore not considered a classic fertilizer. It serves as a mineral soil additive that enriches the soil with valuable trace elements and thus improves soil quality. The composition of stone powder varies greatly depending on the source rock. Lava rock, for example, contains significantly more iron compounds than basalt or diabase powder.