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Black Basalt Cobble is suitable for driveways and walkways and depending on the thickness, it can be sand-set or mortar-set. Stone is a natural product, please expect color variation.

Pictures shown are representations ONLY. Sizes are approximate & may vary slightly with each order. Call for samples of the current batch.

Custom sizes & finishes are subject to minimum quantity & lead time. Stock LA Warehouse.

Usage: Suitable for commercial & residential; Interior & exterior applications, including Freeze/Thaw.


CobbleTop Flamed, 5 Sides Sawn4" x 4"2"Stock
CobbleTop Flamed, Chipped Edges4" x 4"3"Limited Stock
  • Exterior Cladding: Yes
  • Exterior Pavers: Yes
  • Interior Walls: Yes
  • Interior Floors: Yes
  • Kitchen Countertops: 
  • Other Countertops:
  • Wet Areas: 
  • Traffic: Commercial & Residential

Basalt is a dense, volcanic stone, ranging in color from light grey to deep black, depending on the origin of the quarry. Basalt is prized for its hardness, fine-grained texture, and uniformity of color, though as with all-natural stone, variation does occur and only adds to its beauty.

Rock Mill always recommends that a licensed tile contractor be consulted for complete and proper installation guidance. The surface upon which the Basalt will be installed should be clean, solid, even, and without cracks. Installation should not be started until the substrate meets these conditions. For vertical surfaces, the wall should be straight without dents. Basalt tiles should be installed using a high-strength latex modified thin-set, such as LATICRETE 254 Platinum or fortified Portland cement-based thin-set mortar, such as LATICRETE 4237 Latex Additive mixed with LATICRETE 211 Powder. Application: Apply mortar to the substrate with the flat side of the trowel, pressing firmly to work into the surface. Comb on additional mortar with the notched side. Note: Use a properly sized notched trowel to insure full bedding of the tile. Spread as much mortar as can be covered with tile in 15–20 minutes. Do not leave trowel marks. To avoid moisture absorption through the Stone (“shadowing”) and for optimal adhesion, it is essential that each tile be back-buttered and fully bedded for firm support. Place tiles into a wet, sticky mortar and beat in using a beating block and rubber mallet to embed tile and adjust the level. Check mortar for complete coverage by periodically removing a tile and inspecting bedding mortar transfer onto the back of the tile. If the mortar is skinned over (not sticky), remove and replace it with fresh mortar. Grouting: Grout installation after a minimum of 24 hours curing time at 70°F (21°C).

After the grout has dried and the stone surface has been thoroughly wiped clean, apply a high-quality, penetrating sealer, such as Rock Shield Sealer, which is an impregnating, invisible, and breathable sealer that protects exposed natural stone, tiles, pavers, concrete, and grout from damage caused by water, salts, and oil-based stains. Treated indoor and outdoor surfaces become easier to clean, maintain and will look better longer. Rock Shield Sealer can be purchased from Rock Mill. It is important that sealer be applied according to Rock Mill’s instructions. Apply sealer until the surface is saturated. Distribute evenly to prevent pooling.

Please inspect ALL material upon receipt. Claims will not be honored after installation. Rock Mill considers the actions of the installer/contractor/3rd party that customer authorizes to pick up the material to be the responsibility of the customer.

Rock Mill will not honor claims made by the customer, due to unauthorized or improper installation by customer’s installer/contractor. Please ensure that a sufficient quantity of stone is initially ordered to complete the job.

Add-on orders purchased later may vary slightly as new batches may come from different parts of the quarry and will not be guaranteed to match the original order.

All items that are stocked are located at the Rock Mill Gardena, California warehouse.

For more information, please contact your Rock Mill rep or visit our website. Thank you!