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Technical Properties of Natural Stone: EN Standards & Practical Guide

When selecting natural stone for a project, the technical data sheet is your primary reference. It contains the values that determine how the stone will behave under load, exposure, and use. In Europe, the EN standards – notably EN 1936 (physical and mechanical properties), EN 1926 (water absorption), EN 12372 (abrasion resistance), EN 13755 (frost resistance), and EN 14157 (chemical resistance) – provide a common language for manufacturers and users. This guide explains the key parameters, typical ranges for the most common Carrara stones, how to interpret a technical sheet, and the meaning of CE marking and related certifications. It is written for architects, designers, contractors and buyers who need precise, honest, and practical information to make informed decisions.

Apparent Density & Open Porosity

Apparent density is the mass of a stone sample divided by its total volume, including pores. It is expressed in kg/m³ and typically ranges from 2,600 to 2,900 for Carrara marble, 2,800 to 3,100 for granite, and 2,700 to 3,000 for quartzite. Open porosity, the percentage of voids that can be filled with water, is usually 0.5–2.5 % for marble, 0.3–1.5 % for granite, and 0.2–1.0 % for quartzite. High porosity increases water absorption and reduces durability, so a lower porosity is preferred for high‑traffic or outdoor applications.

Water Absorption

Measured by immersing a sample in water for 24 h and calculating the weight gain. EN 1926 defines the maximum permissible absorption: 0.5 % for marble, 0.3 % for granite, and 0.2 % for quartzite. Stones with absorption above these limits are unsuitable for exterior use or for areas exposed to moisture. In practice, Carrara marble often shows 0.3–0.6 %, while high‑grade Carrara can be below 0.4 %.

Compressive & Flexural Strength

Compressive strength (EN 1936) is the maximum load a stone can bear before crushing. Typical values: 70–120 MPa for marble, 120–200 MPa for granite, and 100–180 MPa for quartzite. Flexural strength (EN 1936) is the load at which a beam fails; ranges are 10–25 MPa for marble, 20–35 MPa for granite, and 15–30 MPa for quartzite. These figures guide slab thickness and support design. For example, a 20 mm marble slab can safely support a 1 m² area with a 1 m support span if the compressive strength is above 90 MPa.

Abrasion Resistance (EN 12372)

Abrasion resistance is expressed as the number of cycles a stone can endure before a 1 mm loss of thickness. Marble typically shows 2,000–4,000 cycles, granite 4,000–8,000, and quartzite 5,000–10,000. Higher values indicate better wear resistance, essential for kitchen countertops, flooring, and high‑traffic corridors.

Frost Resistance (EN 13755)

Frost resistance is the stone’s ability to withstand freeze–thaw cycles. The standard classifies stones as A (excellent), B (good), C (moderate), D (poor). Carrara marble usually falls into class B, granite into A, and quartzite into A or B depending on porosity. For outdoor cladding or paving, choose class A or B stones.

Mohs Hardness & Chemical Resistance (EN 14157)

Mohs hardness is a qualitative scale: marble 3–4, granite 6–7, quartzite 7–8. Harder stones resist scratching and staining. EN 14157 tests resistance to acids and alkalis; marble is vulnerable to acidic cleaners, while granite and quartzite are more tolerant. Use pH‑neutral or alkaline cleaners for marble surfaces.

Reading a Technical Sheet & CE Marking

A technical sheet lists: stone type, quarry, batch number, density, porosity, water absorption, compressive/flexural strength, abrasion cycles, frost class, hardness, and chemical resistance. The CE mark indicates conformity with EN 1469 (natural stone), EN 12058 (engineered stone), and EN 12057 (stone slabs). Look for the CE logo, the stone’s classification, and the certification body’s name. The sheet should also provide the stone’s grade (e.g., A, B, C) and any special treatments (e.g., sealing).

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