#4 Stone vs Lava Rock: Size, Cost, and Which to Use

#4 Stone

Sieve size #4 in the ASTM aggregate grading means most of the stone passes a 1.5-inch screen and stays on a 3/4-inch screen. In practice you get a pile of roughly walnut to golf ball sized rock. Every piece is angular because it was crushed, and those sharp edges lock together under load instead of rolling like river stone. Because it is washed or screened clean, there are no fines to fill the gaps between pieces. That is the whole point: about 35 to 40 percent of a pile of #4 is air, so water moves through it fast.

Lava Rock

Lava rock is a lightweight, porous volcanic stone commonly used in landscaping. Its rough texture helps retain moisture while allowing airflow to plant roots.

#4 Stone

• ✓ Driveway and road base
• ✓ Drainage beds
• ✓ Retaining wall backfill
• ✓ Construction entrance pads
• ✓ Pipe bedding for large pipe
• ✓ Erosion control

Lava Rock

• ✓ Landscaping
• ✓ Garden beds
• ✓ Decorative ground cover

#4 Stone

• + Excellent drainage with 35 to 40 percent void space
• + Bridges soft ground better than smaller stone
• + Cheap, $20 to $40 per ton, and stocked everywhere
• + Angular pieces lock together under load
• + Same price as #57 with more drainage capacity

• − Too coarse to walk on or drive on as a surface
• − Needs a finer cap layer for any traffic
• − Hard to rake and spread by hand
• − Sinks into soft clay without fabric

Lava Rock

• + Very lightweight
• + Excellent moisture retention
• + Decorative appearance

• − Breaks down over time
• − Sharp edges
• − Can scatter easily

#4 Stone

#4 stone is crushed rock screened to pieces between 1 and 1.5 inches, with some quarries running it up to 2 inches. It is angular with sharp fractured faces. Color follows the quarry: gray or blue-gray limestone in the Midwest and Northeast, gray to pink granite in the Southeast, tan limestone in Texas.

Lava Rock

Typically 3/4"–1.5" sizes. Red or black.