Basalt
Basalt is a dense, fine-grained volcanic igneous rock supplied dense, vesicular or as cast basalt, with 2.9 g/cm³ density, 15 MPa tensile strength, 70 GPa modulus, 1.7 W/m·K thermal conductivity and service to 400 °C.
Reference datasheet — Basalt is not in the instant-quote catalog. Upload your part and an engineer will quote it in this grade or suggest the closest stocked equivalent.
Values for the DENSE condition
Basalt tempers and conditions
Basalt is supplied in 3 conditions, soft to hard. DENSE is the default FabDigit quotes; the values on this page are for it.
Compare all 3 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
gas-pored volcanic stone | Pick for lightweight cladding, landscaping, filter media and rustic finishes where low weight and texture beat strength. | 6 | 0.8 W/m·K | |||
DENSEDefault Dense basalt | Standard choice for paving, curbing, cladding and heavy-duty floors where strength and abrasion resistance matter. | 15 | 2 W/m·K | |||
As cast | Choose for abrasion liners in chutes, cyclones and slurry/pneumatic conveying pipes — hardest and strongest basalt form, but brittle and impact-sensitive. | 25 | 2 W/m·K |
What is Basalt?
Basalt is a dense, fine-grained volcanic igneous rock supplied dense, vesicular or as cast basalt, with 2.9 g/cm³ density, 15 MPa tensile strength, 70 GPa modulus, 1.7 W/m·K thermal conductivity and service to 400 °C. Engineers use it for paving, curbing, heavy-duty flooring and wear liners because of its high compressive strength, abrasion resistance and chemical resistance (rating 85), and the same melt is drawn into basalt fibre. It is the hardest stone here to process — machinability 12, wet diamond tooling only — so cutting is slow and unit cost rises with detail; granite is easier to fabricate where abrasion demands are lower. Basalt has a density of 2.9 g/cm³ (0.105 lb/in³), heavier than 98% of natural material grades. It melts at 1,200°C (2,192 °F). Basalt has a tensile strength of 15 MPa (2.18 ksi), weaker than 64% of natural material grades. Elongation at break is 0.05% and the elastic modulus is 70 GPa (10.2 Msi).
What is Basalt used for?
- Paving stones and curbs
- Building facades
- Countertops
- Fiber production (basalt fiber)
Advantages
- Stiff — 70 GPa (10.2 Msi), better than 98% of natural material grades
- Low embodied carbon — 0.07 kg CO₂/kg, better than 98% of natural material grades
- Tough — resists crack growth — 1.5 MPa·√m (1.37 ksi·√in), better than 97% of natural material grades
- High service temperature — 400°C (752 °F), better than 94% of natural material grades
- Good corrosion resistance — 85/100, better than 90% of natural material grades
Limitations
- Heavy — 2.9 g/cm³ (0.105 lb/in³), worse than 98% of natural material grades
- Difficult to machine — 12/100, worse than 98% of natural material grades
- Limited ductility — 0.05%, worse than 94% of natural material grades
Basalt properties
Typical room-temperature values for Basalt-DENSE; bars are the position among natural material grades.
Physical3
Basalt has a density of 2.9 g/cm³ (0.105 lb/in³), heavier than 98% of natural material grades. It melts at 1,200°C (2,192 °F).
Mechanical12
Basalt has a tensile strength of 15 MPa (2.18 ksi), weaker than 64% of natural material grades. Elongation at break is 0.05% and the elastic modulus is 70 GPa (10.2 Msi).
Thermal5
Basalt is rated for continuous service to 400°C (752 °F). It conducts heat at 1.7 W/m·K (0.982 BTU/hr·ft·°F), better than 82% of natural material grades. Thermal expansion is 6.5 µm/m·K (3.61 µin/in·°F).
Electrical1
Basalt has an electrical resistivity of 10,000 Ω·m.
Chemical & Environmental1
Corrosion resistance is excellent (85/100), better than 90% of natural material grades.
Sustainability4
Producing a kilogram of Basalt takes about 1 MJ of energy and emits 0.07 kg of CO₂ — less than 98% of natural material grades. Typical recycled content is 0%.
Manufacturability2
Basalt's machinability is not recommended (12/100, worse than 98% of natural material grades).
Common Calculations4
Values are nominal handbook figures for design screening. Certified mill or lot data ships with every FabDigit order on request.
Working with Basalt
Is Basalt easy to machine?
Diamond blades, core bits and CNC stone routers with copious water only; carbide tooling dulls almost instantly and dry cutting risks silica dust and thermal cracking.
Can Basalt be welded?
Not weldable — joints are made with mechanical anchors, epoxy/polyester stone adhesive or cement mortar setting beds; cast basalt liners are bedded in putty and steel-clamped.
Can Basalt be formed, bent or molded?
Shaped by sawing, splitting/guillotining and profiling in the block state; cast basalt is melt-poured at ~1250–1400 °C into moulds and crystallised in an annealing tunnel over 20–30 h.
Basalt chemical composition (wt %)
Limits by weight percent from the governing specification, written the way the spec states them — a single maximum for impurities, a range for alloying elements, and the base element as balance. Nominal is the typical mid-range value.
| Element | Spec limit (wt %) | Nominal |
|---|---|---|
| SiO2range defining a basic (mafic) rock | 45 – 52 | 49 |
| Al2O3 | 13 – 17 | 15 |
| FeO+Fe2O3total iron oxide | 8 – 14 | 11 |
| CaO | 8 – 12 | 10 |
| MgO | 4 – 10 | 7 |
| Na2O | 1.5 – 4 | 2.8 |
| K2O | 0.3 – 2 | 1 |
| TiO2 | 0.8 – 2.5 | 1.5 |
| MnO | 0.1 – 0.25 | 0.15 |
| P2O5 | 0.1 – 0.5 | 0.25 |
| other oxides / LOIBalance: trace oxides and LOI; plagioclase+pyroxene±olivine+magnetite | balance |
What surface finishes work on Basalt?
Common finishes are sawn, honed, flamed (bush-hammered), water-jet or polished; fine grain gives a uniform dark polish, and impregnating sealers are used to cut water absorption and iron staining.
How much does Basalt cost?
Basalt is a budget-cost natural material ($), cheaper than about 90% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
Basalt — frequently asked
What is Basalt used for?
Basalt is typically used for paving stones and curbs, building facades, countertops and fiber production (basalt fiber). In short: highest abrasion resistance in stone; hardest stone to machine; melt-castable as wear liners.
What is the tensile strength of Basalt?
Basalt has a typical tensile strength of 15 MPa (2.18 ksi) — weaker than 64% of natural material grades. Strength varies by condition: see the 3 listed tempers.
Is Basalt easy to machine?
Not especially — machinability is rated not recommended (12/100, worse than 98% of natural material grades). Diamond blades, core bits and CNC stone routers with copious water only; carbide tooling dulls almost instantly and dry cutting risks silica dust and thermal cracking.
Can Basalt be welded?
Not weldable — joints are made with mechanical anchors, epoxy/polyester stone adhesive or cement mortar setting beds; cast basalt liners are bedded in putty and steel-clamped.
What surface finishes work on Basalt?
Common finishes are sawn, honed, flamed (bush-hammered), water-jet or polished; fine grain gives a uniform dark polish, and impregnating sealers are used to cut water absorption and iron staining.
Can Basalt be formed, bent or molded?
Shaped by sawing, splitting/guillotining and profiling in the block state; cast basalt is melt-poured at ~1250–1400 °C into moulds and crystallised in an annealing tunnel over 20–30 h.
What is the maximum service temperature of Basalt?
Basalt is rated for continuous use to about 400°C (752 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
How much does Basalt cost?
Basalt is a budget-cost natural material ($), cheaper than about 90% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
Sources
- ASTM C97/C97M — Absorption and Bulk Specific Gravity of Dimension Stone — ASTM (2018)
- ASTM C170/C170M — Compressive Strength of Dimension Stone — ASTM (2016)
- ASTM C99/C99M — Modulus of Rupture of Dimension Stone — ASTM (2018)
- EN 1469 — Natural stone products, slabs for cladding — CEN (2015)
- Handbook of Physical Properties of Rocks — CRC Press (1982)
- Rock Mechanics and Engineering — elastic constants and K_IC compilations (ISRM) — ISRM (2017)
- Cast basalt wear-protection liners (ABRESIST/Kalenborn-type) technical data — producer (2020)
Property data is compiled from published supplier and standards handbooks and normalised for comparison; hardness values on non-Brinell scales are converted approximately for charting only. Manufacturability limits are FabDigit quote-engine defaults and may be relaxed by engineering review. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.