Rock flour (rock dust)

Finely ground rock, such as basalt, serpentinite or mica schist, used as a mineral input.

Characteristics

Supplies silicon, calcium, magnesium, potassium, iron and trace elements.
Composition varies widely with the parent rock.
Releases minerals slowly as it weathers in the soil.
Cited as a mineral ingredient in mineralised biol and bokashi recipes.

Role in the preparation: Adds a mineral fraction to biol, bokashi or compost.

Caution: Wear a dust mask, since fine rock dust may contain crystalline silica, and ask the supplier for an analysis.

Sources: UAJMS (Bolivia) - Harina de rocas para uso agricola en Tarija · NCAT - University of Florida testing basaltic rock dust as soil amendment · Argentina.gob.ar - Impulsan el uso de abonos liquidos fermentados

Documentary information: this is neither a recommendation for use nor a plant-protection or veterinary claim. Check your country's regulations before any use.