The Negro Pinta and Negro Laguna Marbles from Alconera (Extremadura, Spain) are distinguished by their depth of color and versatility in finishes, ranging from mottled and veined blacks to uniform, intense tones.
These varieties combine aesthetic elegance with technical performance comparable to Grey Marengo, but with a more sober and exclusive character, making them ideal for high-prestige projects.
Extracted from the María del Carmen Concession (VALEXMAR), they are part of one of the marble quarries with vast reserves in Spain, with geological continuity ensuring stable supply and a long history of use in public works, restoration, and contemporary architecture.
Identification
- Petrographic family: Calcite-dolomitic marble (predominantly calcitic metacarbonate rock)
- Origin / Quarry: Alconera (Badajoz, Spain) · María del Carmen Concession (VALEXMAR)
- Chromatic description:
- Negro Pinta: Transitional variety from Grey Marengo to Negro Laguna, with slight chromatic and grain homogeneity variations; due to geological continuity, its technical properties and composition are analogous to those of Negro Laguna and Grey Marengo.
- Negro Laguna: Deep black marble with areas of very dark grey and occasional whitish streaks or veins, whose intensity varies depending on the extraction area.
Technical Properties (UNE-EN Standards)
(Actual test values for Negro Laguna and estimated for Negro Pinta by geological continuity within the same concession; specific validation by batch recommended.)
- 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): ≈ 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): ≈ 2 J
- 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 (ASTM E1980): **
Chemical Composition
- No specific analysis available for the black varieties; being a natural transition from Grey Marengo within the same deposit, an equivalent chemical composition is assumed.
Nevertheless, a specific study is recommended depending on the intended use of the material. - See Grey Marengo Technical Data Sheet >
Remarks
- Materials from the same exploitation unit as Blanco Alconera and Grey Marengo, with quarry continuity and progressive tonal variation towards intense blacks.
- High density and low porosity → suitable for exterior use under demanding conditions.
- Information marked with asterisk or italics is indicative and comes from:
- Tests performed on other materials from the same deposit which, by analogy and continuity, would yield similar values.
- External sources and sectoral platforms for dolomitic marble:
- ** The available SRI test was performed for Grey Marengo with an average result of ≈ 54.4. By geological continuity of the deposit, a slightly lower value is expected for the black varieties. 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
- Urban and landscaping elements
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 · NG LAG / NG PIN
- Version: TF-NG-LA-v2025.02 and TF-NG-PI-v2025.02