Sedimentary Stone

Limestone

Anatolia & Indiana, USA

ASTM C568 Compliant

Limestone is a sedimentary rock composed primarily of calcite (calcium carbonate) derived from marine organisms — shells, coral, and algae. Formed over millions of years from ocean sediment, limestone often retains visible fossil inclusions that add character to the stone. Indiana limestone (Salem Limestone) is the ben...

Technical Specifications
Mohs hardness
3–4
Water absorption
1.1%
Freeze-thaw
Good — dense grades
Density
2.55 g/cm³
Cost range $8–18 / sq ft
Price Range $8–18 / sq ft
Applications

Where Limestone is used

  • Exterior facade cladding
  • Building trim and cornices
  • Flooring (interior and exterior)
  • Paving
  • Countertops
  • Pool coping
  • Retaining walls
  • Landscape features
Climate Suitability

Regional performance

Dense Grade II limestone (ASTM C568 ≤0.75% absorption) is rated for all North American climate zones including extreme freeze (Minnesota, Montana, Quebec). Lighter grades require protected installation in freeze zones.

Care & Maintenance

Limestone maintenance guide

Seal exterior limestone every 12 months; interior every 18–24 months. Clean with pH-neutral detergent. Remove biological growth (moss, algae) with diluted algaecide rated for natural stone — never pressure wash aggressively. Treat efflorescence promptly with efflorescence remover. For carving and decorative limestone: consult a stone conservator before applying any products.

FAQ

Common questions about Limestone

Is limestone porous?

Limestone porosity varies by grade. Dense Indiana limestone (Grade II): 0.75% max absorption — suitable for exterior in all climates. Medium limestone: 2–5% absorption — suitable for interior and protected exterior. High-porosity grades: 5%+ — interior only. Always specify the ASTM C568 grade for your application. All limestone benefits from sealing.

What is Indiana limestone?

Indiana limestone (Salem Limestone, technically) is a buff/grey oolitic limestone quarried from Lawrence and Monroe Counties, Indiana. It is one of America's most important building stones — used in the Empire State Building, National Cathedral, Pentagon, and thousands of civic buildings. It is rated ASTM C568 Grade II and is available in fine, medium, and coarse grain textures. SmartStones lists Indiana limestone fabricators and suppliers.

Can limestone be used outdoors in Canada?

Yes — dense Indiana limestone and Turkish limestone in ASTM C568 Grade II (≤0.75% absorption) are rated for all Canadian climate zones including hard-freeze provinces. Install with proper drainage slope, use air-entrained mortar, and provide expansion joints every 8–10 ft. Seal annually. Many major Canadian civic buildings use Indiana limestone successfully.

Geology

How Limestone forms

Limestone is a sedimentary rock composed primarily of calcite (calcium carbonate) derived from marine organisms — shells, coral, and algae. Formed over millions of years from ocean sediment, limestone often retains visible fossil inclusions that add character to the stone. Indiana limestone (Salem Limestone) is the benchmark North American dimension stone, quarried from a single geological formation in Lawrence County, Indiana since the 1820s. Turkish limestone from Anatolia is a major export to North American markets.