The company Alfredo Polti SA, a typical family business, is active in the industrial sector of natural stone. It was founded by Alfredo Polti in 1950, with the launch, in Grono, of a workshop for the processing of the Gneiss Calanca. The pioneer was however Alfredo’s father, Giovanni Polti, who in 1920 was involved in the extraction and processing of the Gneiss Calanca in the quarries of Arvigo, where in 1960 Alfredo Polti transferred the entire production. The extraction of the stone from its own quarries and its elaboration in new and modern laboratories thus became two integrated phases of a single production process. The Gneiss Calanca extracted from the quarries Alfredo Polti SA is treated in modern laboratories, where expert stonemasons transform it manually or mechanically, thanks to the help of the most modern machines for working with stone. Moreover, part of the material is put on the market in the raw state, in the form of blocks, irregular or quadrangular slabs, or masonry stones. The available offer is vast and includes products for: • the substructure • the superstructure • the construction and furnishing of parks, gardens, squares and cemeteries • the creation of artifacts able to satisfy the most demanding dictates of modern architecture of exteriors and interiors. About 90% of production is destined for the Swiss domestic market. The remainder is exported, in particular to Germany, Italy, Austria and France. In many cities of these countries you can admire important works realized with the Gneiss Calanca by Alfredo Polti SA produced in Arvigo. After the death of the founder Alfredo Polti, the company was taken over by: Giovanni Polti, who takes care of the extraction and production processes and Vania Polti Ambrosini, who guarantees administrative management. Since 2013, Alfredo Polti SA remains the only active quarry in the Calanca valley. Most of Alfredo Polti SA's collaborators have many years of service in the company, synonymous with experience and professionalism at the service of customers. Since May 2007 the company is ISO 9001 certified.