Type of stone: Gneiss (with a composition identical to granites)
Quarry: Arvigo, Val Calanca, Grison, Switzerland
Peculiarities: Calanca Gneiss belongs to the silicate hard rocks and is thus suitable for both indoor and outdoor use, even with heavy frosts under complete water saturation and the additional effects of de-icing salt. It has good mechanical properties (abrasion resistance, compressive and flexural strength) and is also resistant to aggressive chemicals.
History: The history of this natural stone began long before the Alps were formed. Originally it must have been sediments from the erosion of older rocks. Today’s stone was formed in a process of metamorphosis deep in the Earth’s crust under high pressure and temperature. It was brought back to the surface in an alpine folding combined with the erosion of the layers above. Geologically the Calanca Gneiss belongs to the crystalline nappes of the Ticino culmination which is a major tectonic structure of the Alps.
Application: inside and outside
Edges: sawn, broken, rough broken
Contact: Alfredo Polti SA
Industria del Granito
Via alla Sega, CH-6543 Arvigo
Photos: Alfredo Polti
(31.07.2018, USA: 07.31.2018)