Black Lava Rock ,Average Size Stones 1/2", 6 Quarts Per Package. MIGHTY109 Black Lava 1/2 +- size stone. 6 Quarts Great as a ground cover or for garden paths and planter beds Bold black and gray color tones. Also good for Fire Pits Helps to maintain moisture, aerate soil, prevent erosion, and improve drainage. Course and porous stone. Very light weight.