#57 Gravel vs Lava Rock: Size, Cost, and Which to Use

#57 Gravel

The 57 comes from the ASTM C33 grading table. Size #57 means most of the stone passes a 1-inch screen and stays on a #4 sieve (about 3/16 inch), with the bulk of it between 1/2 and 1 inch. It is "clean" stone, so there are no fines. That leaves about 35 percent air space in a pile, which is why it drains so well and why it stays loose on its own.

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.

#57 Gravel

• ✓ Driveways
• ✓ French drains
• ✓ Concrete mix
• ✓ Pipe bedding
• ✓ Backfill
• ✓ Parking pads
• ✓ Septic systems

Lava Rock

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

#57 Gravel

• + Cheapest useful stone at $20 to $35 per ton
• + Stocked at every quarry in the country
• + Drains fast, about 35 percent void space
• + Angular pieces interlock under load
• + Works for driveways, drains, concrete, and backfill

• − Too coarse to walk on comfortably
• − Stays loose, rolls to the edges under tires
• − Needs a finer top layer on driveways
• − Not decorative

Lava Rock

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

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

#57 Gravel

#57 gravel is angular crushed stone screened to 3/4 inch to 1 inch, with a few pieces down to 1/2 inch. Color depends on the quarry: gray or blue-gray limestone through the Midwest and Northeast, gray, white, and pink granite in the Southeast, tan limestone in Texas, and dark basalt in the Northwest.

Lava Rock

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