2015 GSA Annual Meeting in Baltimore, Maryland, USA (1-4 November 2015)

Paper No. 152-3
Presentation Time: 2:00 PM


PIERO PRIMAVORI, P.P., Free-Lance- International Consultant, Via Livornese, 1, Pisa, 56122, Italy and ANDREA ANGHEBEN, A.A., Consorzio Italiano Porfido del Trentino soc. cons. coop, TRENTO, 38121, Italy, pieprima@gmail.com

Porphyry has been known about and used since ancient times. Important relics have been discovered at Assyrian-Babylonian, Egyptian and Roman sites, the cradles of civilisation. In Roman times, the red porphyry, thus called due to its purple-red color (in Latin “Porphyra”), was a symbol of prestige and royal circumstance. The title “porfirogenito” meant “born in a room which was completely tiled with porphyry”, and these rooms only existed in the palaces of the powerful. Many emperors were buried in sarcophagi of porphyry.

Porphyry is a name historically used for commercial purposes by both stone operators and clients/customers; geologically speaking, it is a Permian volcanic rock constituted by rhyolitic-rhyodacitic ignimbrites, belonging to the “Atesine Porphyric Platform”, a huge and complex volcanic unit, 7.500 km2 large and 2 km thick.

Extraction is currently carried out in the province of Trento and municipalities of Albiano, Cembra, Giovo, Capriana, Lases, Baselga di Pinè e Fornace, Trentino-Alto Adige region, N Italy.

Although porphyry is being produced in other places of the world (Argentina, Mexico, Iran, China, Bulgaria etc.) none of these production can boast of the same product range or – above all – the same properties that Trentino porphyry can provide; this stone has proved to be one of the most weather-resistant and durable rocks in all its planetary applications. Such a uniqueness is due to the excellent physical-mechanical properties, a peculiar mix among chemistry, mineralogy, texture and structure of the stone.

Porphyry was first introduced in the cube pavings on the main roads throughout Trentino and Südtirol, and it rapidly became one of the most important materials for paving and facing in Europe. Its versatility ranges from cubes, crazy paving, kerbs and setts to stairs and steps, up to recent examples of urban attractive design, streetscaping of historical centres, furnitures etc., where also the sustainability aspects of the stone use are taken into maximum account.

Nowadays, the porphyry is the symbol of the Trentino stone industry, and rightly so: its importance in productive, social, employment, economic and cultural terms is undisputed. Porphyry is by far the province’s most important socio-economic activity, as well as being one of the biggest stone production districts nationwide.