What Is Basalt?
Basalt is a dark-colored, fine-grained volcanic rock formed from rapidly cooling lava. It is the most common volcanic rock on Earth, covering vast areas of the ocean floor and forming extensive lava plateaus on continents. For the construction industry, basalt offers a unique combination: the durability of granite with a distinctive dark, uniform appearance — at a more competitive price point than most dark granites.
China has major basalt reserves in Fujian, Hainan, and Inner Mongolia provinces, with established quarrying and processing infrastructure. Chinese basalt is exported globally as paving cubes (setts), kerbstones, tiles, dimension stone, and crushed aggregate. It is particularly popular in European markets — Germany, Netherlands, Belgium, and the UK — where basalt paving has been used for centuries.
Key Properties
| Property | Basalt | Granite (for comparison) |
|---|---|---|
| Hardness (Mohs) | 5-7 | 6-7 |
| Compressive Strength | 200-400 MPa | 100-250 MPa |
| Water Absorption | 0.1-0.3% | 0.2-0.5% |
| Density | 2.8-3.0 g/cm³ | 2.6-2.8 g/cm³ |
| Abrasion Resistance | Excellent | Excellent |
| Frost Resistance | Excellent | Excellent |
| Color | Dark grey to black (uniform) | Wide variety |
Basalt actually outperforms granite in compressive strength and water absorption — it is one of the hardest-wearing natural stones available. Its uniform dark color, while less varied than granite, is precisely what makes it desirable for specific architectural applications.
Applications
Basalt Paving Cubes (Setts)
The most internationally traded basalt product. Small cubes (typically 8-10cm or 10-12cm) used for traditional cobblestone paving. Basalt setts are specified for historic town centers, pedestrian zones, driveways, and decorative paving patterns across Europe. Standard finishes: natural split (top and bottom), flame-treated, or bush-hammered for slip resistance. Chinese basalt setts are exported in bulk (ton bags) or on pallets, typically 25-27 tons per 20ft container.
Basalt Kerbstones
Road and pavement edging in standard profiles. Basalt kerbs are specified for their durability under vehicle impact and resistance to de-icing salts. Standard dimensions: 1000×300×150mm, 1000×250×125mm, or custom. Finishes: flamed, bush-hammered, or polished top surface.
Basalt Tiles and Slabs
For interior and exterior flooring, wall cladding, and architectural features. Basalt's dark, uniform color creates dramatic, contemporary interiors. Popular sizes: 300×300mm, 400×400mm, 600×400mm, 600×600mm, and cut-to-size. Thickness: 10-20mm (interior), 20-40mm (exterior).
Basalt Dimension Stone
Large-format pieces for steps, benches, water features, and landscape architecture. Cut to order from selected blocks.
Crushed Basalt Aggregate
For concrete production, road base, railway ballast, and asphalt. Basalt aggregate is preferred where high compressive strength and wear resistance are required. Not typically exported as finished product from China due to low value-to-weight ratio, but available for domestic Chinese projects.
Basalt vs. Dark Granite — What's the Difference?
This is the most common question from B2B buyers considering basalt. The practical differences:
- Appearance: Basalt is more uniformly dark with a finer grain. Dark granites (Absolute Black, Black Galaxy) have visible crystal structure and may contain flecks of other minerals. If you want absolute color consistency, basalt may be the better choice.
- Price: Basalt is typically 15-25% less expensive than premium dark granite (Absolute Black, Shanxi Black). For budget-sensitive projects requiring a dark stone, basalt offers excellent value.
- Slip resistance: Basalt's fine grain provides naturally good grip, comparable to flamed granite.
- Weathering: Some basalts contain iron minerals that can oxidize (rust) over decades of exterior exposure, creating subtle brown tones. This is considered a feature by some architects and a defect by others — always discuss with your supplier.
Quality Specifications for B2B Orders
When ordering basalt products from China, specify:
- Product standard: EN 1341 (slabs/paving), EN 1342 (setts), EN 1343 (kerbs) for EU markets; ASTM C615 for US
- Dimensional tolerance: ±2mm for setts, ±1mm for calibrated tiles
- Finish: Natural split, flamed, bush-hammered, honed, polished
- Edge treatment: Sawn edges or hand-dressed (traditional appearance)
- Shipping format: Bulk bags, pallets, or crates per destination requirements