Maggia is a dark grey gneiss, very schistose and with a fine grain.
Its name derives from the geographical location where it is extracted, the Maggia Valley.
This rock is mainly composed of light quartz, white feldspar and large amounts of biotite (dark mica), which alternate with feldspar to form a light-dark band. Maggia belongs to the same geological formation as Onsernone gneiss.
The gneiss from the Maggia Valley is highly resistant to frost, acids and alkalis.
References for use of the material
Church of St. John the Baptist, architect Mario Botta, Mogno (Switzerland).
Main source of description
Material-Archiv. (2023). Maggia.
Original source of characteristic values
Kündig, R. (1997). Die mineralischen Rohstoffe der Schweiz. Schweizerische Geotechnische Kommission.
