ARABESCATO OROBICO: A NOMINATION FOR “GLOBAL STONE HERITAGE RESOURCE”

The Arabescato Orobico (A.O.) is a decorative stone from the Bergamasc Alps, Italy. Geologically speaking, it belongs to the Calcare Rosso unit (Ladinian-Carnian), a peritidal tepee-rich limestone modified by superimposed diagenetic processes, outcropping in Lombardy basin, Southern Alps. Four commercial types are identified, Grigio, Grigio-Rosa, Rosa and Rosso, even if almost eleven different subtypes have been codified. The Calcare Rosso outcropping area is located between Como Lake and Valcamonica, over an area 75x15 kms wide; the quarrying area is located in Brembana and Seriana Valleys, Bergamasc Alps. In the Brembana Valley there are 3 active quarries and some processing plants, while the Seriana Valley district is abandoned since the 70s of the last century. The activities date back to almost the 18th Century in Brembana Valley, probably older in Seriana Valley; the production peak was registered between the 50s and the 70s of the last century. Currently, the production is limited to 20.000 m3/y.

The A.O. is a high quality niche stone, with unique aesthetic characteristics and represents one of the most striking stones in the small segment of the arabesque colored “marbles”. Significant products on both national and international market are the giant polished slabs for internal floorings and furniture for interior design. Slabs are generally cut against the vein, or perpendicularly to bedding planes, and installed with the “book-match” pattern, to highlight the kaleidoscopic play of colors. Recently, also the cutting along the vein has proposed with one variety (Fiore delle Alpi) to create a more homogeneous effect. Apart from its geological-petrographic, commercial and technical properties, several issues related to the A.O. are considered to be of relevant importance for its designation as a Global Heritage Stone Resource: the distinctive mark on the Italian baroque architecture, the use in modern and contemporary architecture, the original trademark. The so-called “Pietre della Bergamasca” quality seal was released by the local Chamber of Commerce in 2003 for valorizing, diffusing and protecting the cultural identity and tradition of stones extracted in the Province of Bergamo.