Vermiculite Grade A - 3 is a premium, coarse particle size material meeting ASTM C516 Type 1, Grade 2 specifications. Bulk coarse Vermiculite is widely used as a component of growing media for professional growers. Additionally, the material is used as a cover for seed topping. The particle size and absence of fines makes the material ideal for packaging smaller boxes of hazardous chemicals for air transport in accordance with IATA Regulations.