Limestone MD (Class II MD)
Additive grade · default condition
ASTM C568
The standard building limestone (e.g. Indiana-type) for cladding, sills and pavers — best balance of workability and durability.
Values for the MD condition
Other Limestone tempers and conditions
Limestone is listed in 4 conditions; see the grade overview at Limestone.
Compare all 4 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Class I LD | Soft, porous, easily carved stone for interior work and protected exterior detailing. | — | 3 | — | — | 1 W/m·K |
MDDefaultThis page Class II MD | The standard building limestone (e.g. Indiana-type) for cladding, sills and pavers — best balance of workability and durability. | — | 5 | — | — | 2 W/m·K |
Class III HD | Dense, low-absorption limestone for heavy-traffic paving, stair treads and severe-exposure cladding; takes a honed/near-polished finish. | — | 8 | — | — | 3 W/m·K |
Dolomitic limestone | Choose when higher hardness, better acid resistance and a tighter polish than ordinary calcitic limestone are required. | — | — | — | — | 3 W/m·K |
What is Limestone MD?
Limestone MD is Limestone in the MD grade — the standard building limestone (e.g. Indiana-type) for cladding, sills and pavers — best balance of workability and durability. Limestone MD has a tensile strength of 5 MPa (0.725 ksi), weaker than 85% of natural material grades. Elongation at break is 0.05% and the elastic modulus is 30 GPa (4.35 Msi). Limestone MD has a density of 2.4 g/cm³ (0.0867 lb/in³), heavier than 83% of natural material grades.
Advantages
- Low embodied carbon — 0.09 kg CO₂/kg, better than 95% of natural material grades
- High service temperature — 400°C (752 °F), better than 94% of natural material grades
- Stiff — 30 GPa (4.35 Msi), better than 83% of natural material grades
- Conducts heat well — 1.7 W/m·K (0.982 BTU/hr·ft·°F), better than 82% of natural material grades
Limitations
- Limited ductility — 0.05%, worse than 94% of natural material grades
- Needs corrosion protection — 25/100, worse than 88% of natural material grades
- Heavy — 2.4 g/cm³ (0.0867 lb/in³), worse than 83% of natural material grades
Limestone MD properties
Typical room-temperature values for Limestone MD; 13 are specific to this condition. Other listed values are Limestone reference data and may not represent this condition. Bars are the position among natural material grades.
Physical2
Limestone MD has a density of 2.4 g/cm³ (0.0867 lb/in³), heavier than 83% of natural material grades.
Mechanical12
Limestone MD has a tensile strength of 5 MPa (0.725 ksi), weaker than 85% of natural material grades. Elongation at break is 0.05% and the elastic modulus is 30 GPa (4.35 Msi).
Thermal5
Limestone MD 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 µm/m·K (3.33 µin/in·°F).
Electrical1
Limestone MD has an electrical resistivity of 10,000 Ω·m.
Chemical & Environmental1
Corrosion resistance is poor (25/100), worse than 88% of natural material grades.
Sustainability4
Producing a kilogram of Limestone MD takes about 1 MJ of energy and emits 0.09 kg of CO₂ — less than 96% of natural material grades. Typical recycled content is 0%.
Manufacturability2
Limestone MD's machinability is very good (80/100, worse than 52% of natural material grades).
Common Calculations4
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with Limestone MD
Is Limestone easy to machine?
Saws, drills and CNC-carves easily with water-cooled diamond tooling; avoid dry cutting (silica/carbonate dust) and support thin sections against chipping.
Can Limestone be welded?
Not weldable — units are joined with mortar, epoxy/polyester stone adhesives and stainless anchors, dowels or kerf clips.
Can Limestone be formed, bent or molded?
Shaped by quarry block sawing, splitting along bed planes, profiling and hand or CNC carving; never bent or thermally formed.
What surface finishes work on Limestone?
Common finishes are sawn, honed, bush-hammered, sandblasted or tumbled; true high polish only on dense/dolomitic stone, and breathable impregnating sealers are advised against staining and acid rain etch.
Limestone 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 |
|---|---|---|
| CaCO3 (calcite)principal mineral phase | 80 – 99 | 94 |
| MgCO3 (dolomite)up to ~45 % in dolomitic variants | 0.2 – 8 | 2 |
| SiO2quartz/chert impurity | 0.2 – 8 | 2 |
| Al2O3clay minerals | 0.1 – 3 | 0.8 |
| Fe2O3iron oxide, source of buff/tan coloration | 0.05 – 1.5 | 0.3 |
| organic matter / bitumengives grey-blue tones | 0 – 1 | 0.2 |
Limestone MD — frequently asked
What is Limestone MD used for?
Limestone MD is typically used for building facades, flooring and wall cladding, interior decorative trim, landscape and garden features and raw material for lime/cement. In short: easiest-carving building stone; lowest strength stone here; acid-sensitive carbonate stone.
What is the tensile strength of Limestone MD?
Limestone MD has a typical tensile strength of 5 MPa (0.725 ksi) — weaker than 85% of natural material grades. Strength varies by condition: see the 4 listed tempers.
Is Limestone MD easy to machine?
Yes — machinability is rated very good (80/100, worse than 52% of natural material grades). Saws, drills and CNC-carves easily with water-cooled diamond tooling; avoid dry cutting (silica/carbonate dust) and support thin sections against chipping.
Can Limestone MD be welded?
Not weldable — units are joined with mortar, epoxy/polyester stone adhesives and stainless anchors, dowels or kerf clips.
What surface finishes work on Limestone MD?
Common finishes are sawn, honed, bush-hammered, sandblasted or tumbled; true high polish only on dense/dolomitic stone, and breathable impregnating sealers are advised against staining and acid rain etch.
Can Limestone MD be formed, bent or molded?
Shaped by quarry block sawing, splitting along bed planes, profiling and hand or CNC carving; never bent or thermally formed.
What is the maximum service temperature of Limestone MD?
Limestone MD 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.
Sources
- ASTM C568/C568M — Standard Specification for Limestone Dimension Stone — ASTM International (2021)
- ASTM C97 (absorption & bulk density), C99/C880 (modulus of rupture/flexural), C170 (compressive strength) — ASTM International (2018)
- Dimension Stone Design Manual — Natural Stone Institute (MIA+BSI) (2016)
- Indiana Limestone Handbook — Indiana Limestone Institute of America (2007)
- Inventory of Carbon & Energy (ICE) — stone products — University of Bath / Circular Ecology (2019)
Property data is compiled from published supplier and standards handbooks and normalised for comparison. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.