AZOMITE® is a broad spectrum natural mineral product mined from a unique deposit in Utah, USA. The combination and quality of non-crystaline amorphous minerals found in AZOMITE® are distinct from any other mineral deposit in the world. Field Grade mimics a coarse sand. Particle sizes range from 1/8" to powder for both rapid and longer-term results. Field Grade is designed for composting and potting soils, though it is dusty when applied with a broadcast spreader.