Altmühltaler Kalksteine e.V.

Technical Information of Solnhofen Natural Stone

Special Characteristics

The rough surface carries numerous iron and manganese sediments called dendrites. They resemble fern.


All technical data listed on this page are considered as average values.  Deviation from the given norm is possible. BTI structural regulations of the Deutsche Naturwerkstein-Verband (German Natural Stone Association) apply.

yellowish (beige), grey, brownish, reddish
15x15 cm, 15x30 cm, 20x20 cm, 20x40 cm, in 5 cm pattern up to 60x60 cm including free lengths, octagon, hexagon, rose pattern , additionally: polygonal panels
Quarry rough, brushed (satinated), slightly honed, medium honed, fine honed, honed, matt polished
based on format: 7-12 mm, 13-25 mm or calibrated thickness depending on application
In accordance with DIN 18352 and DIN EN 1469, EN 12057 and EN 12058 also on floors with water heating systems or electrical floor heating systems. Floors to be laid according to installation instructions of Altmühltaler Kalkstein e.V.
Maintenance and care Instructions
Water with wax free and non acidic detergents. Care instructions according to Altmühltaler Kalkstein e.V. apply .
Heat Conductivity
(ƛ)=2.3 W/m x k
Water Absorption
approx. 1.4% (according to mass)
approx. 2.58 g/m³
Compressive strength
approx. 157 MPa
Flexural Strength
23.7N/mm² (if under 5% mean quantile value approx. 30.3N/mm²)
Abrasion Resistance according to DIN EN 14157/B (as defined by Böhme)
approx. 14.7 cm³/50 cm²
Abrasion Resistance according to DIN EN 14157 (as defined by Capon)
19.5 mm
Upon testing for radioactivity (gammaspectrometric measurement) performed by the LGA Nürnberg showed the following results in its measuring report for Solnhofen Natural Stone Slabs (M5921 104 A dated 16 April 2002): Values of K-40 with 19 Bq/kg to 15 Bq/kg (Calium 40), Ra-226 with <5.5 Bq/kg to <5.1 Bq/kg (radium 226), TH-232 with <0.4 Bq/kg to 2.1 Bq/kg (thorium 226) were significantly under those described in index 65 (BMU 1987 <37>) "natural radioactive matter in various materials."