Grey Marble Technical Data Sheet – “Gris Marengo”

The Grey Marengo Marble from Alconera (Spain) is internationally recognized for its chromatic homogeneity, strength, and low absorption.
In this entry you will find the Grey Marengo Marble Technical Data Sheet with the physical-mechanical properties verified according to UNE-EN standards, as well as its applications in ventilated facades, paving, restoration, and public works.

This material is extracted under the María del Carmen concession (VALEXMAR), one of the marble quarries for sale in Spain, with vast reserves and a long history of supplying prestigious architectural projects.

Identification

• Petrographic family: Calcite-dolomitic marble (predominantly calcitic metacarbonate rock)
• Origin / Quarry: Alconera (Badajoz, Spain) · María del Carmen Concession (VALEXMAR)
• Chromatic description:
  Homogeneous grey, fine-to-medium grain.

Technical Properties (UNE-EN Standards)

(Joint tests with Blanco Alconera, except SRI which was performed separately)

• Apparent density (EN 1936): 2,730 kg/m³
• Open porosity (EN 1936): 0.2 %
• Water absorption (EN 13755): 0.1 %
• Compressive strength (EN 1926): 148 MPa
• Flexural strength (EN 12372): 17.8 MPa
• Abrasion resistance (EN 14157:2024): 20.5 mm
• Frost resistance (EN 12371, 168 cycles): 0 %
• Slip resistance:
  • CEN/TS 16165:2016 – wet sawn: 50
  • UNE 41901:2017 – bush-hammered wet: 79
  • CEN/TS 16165:2016 – bush-hammered wet: 79
• Impact resistance (UNE-EN 14158:2004): 2J
• Thermal shock aging resistance (UNE-EN 14066:2013): -1.3%
• Reaction to fire (EN 13501-1): (A1 – non-combustible, according to other sources)*
• Elastic modulus (EN 14580): (≈75 GPa, according to other sources)*
• SRI / Solar Reflectance Index (TECNALIA, ref. ASTM E1980): ≈ 54.4
  • Low convection (5 W/m²K): 53.6
  • Medium convection (12 W/m²K): 54.4
  • High convection (30 W/m²K): 55.1

Chemical Composition (Qualitative test)

• Matrix (CaCO₃): 75.46 %
• CaMg(CO₃)₂: 21.93 %
• Traces:
  • FeCO₃: 0.72 %
  • SiO₂: 1.43 %
  • Al₂O₃: 0.46 %
• % oxides (stoichiometric conversion, non-quantitative):
  • CaO: 48.95 %
  • MgO: 4.79 %
  • FeO: 0.45 % (equivalent Fe₂O₃: 0.50 %)
  • SiO₂: 1.43 %
  • Al₂O₃: 0.46 %
  • LOI (≈CO₂): 43.92 %

Remarks

• Physical-mechanical properties similar to Blanco Alconera in joint tests (high compactness, low absorption).
• SRI ≈ 55 confirms its suitability for mitigating the heat island effect in exterior paving under extreme climates.
• Information marked with an asterisk or italics is indicative and comes from:
  • Tests performed on other materials from the same deposit that, by analogy and geological continuity, would yield similar values.
  • External sources and sectoral platforms for dolomitic marble:
    • Focus Piedra
    • StoneContact
• ** The available SRI test was performed for Grey Marengo with an average result of ≈ 54.4. By geological continuity of the deposit, a lower value is expected for darker varieties, though not significantly different. For large projects, batch testing is recommended.

Possible Finishes

Polished · Honed · Bush-hammered · Sandblasted · Brushed · Antiqued · Sawn/ground · Flamed* (subject to technical validation)

Recommended Uses

• Interior cladding
• Interior/exterior flooring (depending on finish and slip resistance)
• Ventilated facades
• Restoration and public works

Certificates / Tests available under NDA

• Analytical Report, University of Alicante, 2021
• Tecnalia Report (SRI)
• VALEXMAR CE Declaration of Performance based on tests by the Marble Technology Center (ENAC accreditation Nº 373/LE817)

• Internal Code: VALEXMAR · GR MAR
• Version: TF-GR-MA-v2025.02