Mineralogical locations
of Piedmont
by Patrizia and Massimo Deidda
Pellice Valley
Seccarezze quarries-Luserna San Giovanni (TO)

We are located in Luserna Valley either side of the Valle Pellice valleys radiating from the town of Luserna San Giovanni (TO).

It arrives in Luserna San Giovanni, coming from Turin, take the motorway to Pinerolo and continue towards Val Pellice, Luserna San Giovanni to continue in the direction of the municipality of Rorà, and in a few km you reach a detour if the signs indicate the Luserna Stone quarries.

For lovers of climbing a stone's throw from the quarries and more specifically a Rocca Ciapel, easily reached from Prinera Township, was equipped with an impressive rock wall.

Picturesque views.

The local economy is mainly based on extraction of Luserna stone, laminated, gneiss is extracted in countless quarries located in its surroundings.

It is believed that the exploitation of quarries dates back to the medieval period, but there are only written documentation from the mid-seventeenth century.

The most representative location where you extract the Luserna stone are located:

Valle Infernotto-Comune di Bagnolo Piemonte (CN)-at Montoso;

Val Luserna-Luserna San Giovanni Municipality (TO)-at Seccarezze;

Val Luserna-municipality of Rorà (TO)-cave of the area of Bonet del Prete.

As the pietra di Lucerna, trade name, it means one of the varieties of gneiss that emerges between the val Pellice and valle Po covering an area of about 50 km.

The laminar gneisses that commercially is named Pietra di Lucerna, is a metamorphic rock composed primarily of quartz, feldspar, mica and other minerals.

There are many applications in the construction field thanks to highly characteristic that is easy to form slabs.

Part of the crude product, named cliff, is primarily used to arm the embankments of the rivers so as to avoid flooding, and reduce environmental impact unlike other alternative materials (concrete).

Is widely used in the construction of new roads.

The finished product is used especially for urban pavement, curbs from the sidewalk and slabs, and in private buildings with stairs, balconies, paving slabs, lintels, sills, roofs, etc.

You can see that in all stages from cultivation up to Luserna stone does not throw away anything, '' TOUT VENANT ''

Formerly the quarrymen, in their laborious work, used hammers, chisels, wedges and ammonium nitrate explosives, today replaced by advanced technologies, hydraulic drifters, earthmoving, detonating cords, black powder, diamond wire.

The firm Granite St. Helena of Bagnolo Piemonte (CN) has been made available to allow authors to documenting the stages of excavation and processing of Luserna stone cave Seccarezze in situ and gave permission to search and subsequent sampling of different minerals.


Steps followed by the author in collaboration with Patrizia Giagnotti.


The unveiling is the first stage of cultivation of the quarry, which will allow the subsequent extraction stages.

Using earth-moving machines (excavators) and the use of explosives, where necessary, removed superficial coverage of the site (capellaccio).


Lamellar gneiss blocks are taken from quarrying banks using primarily the hydraulic drifters.

Once the rock Bank be extracted (there are real growing projects of the quarry) are accomplished with the hole punch vertically inside the rock, the holes are aligned from one another from 20 cm to 30 cm. Are fixed to the rock drill of barramine that can measure from 80 cm to 8.60 meters long, equipped with a special diamond tip drill the rock and retrieve the ammassandola drilling dust into little piles, the main purpose is to prevent this waste into the air and is reused for the Sprint preparation of mine.

Obtained the holes, aligned and parallel, are placed the detonating cords from 3gr-6gr-9 Gr. nut-12gr per cm depending on the piece of rock that you want to remove from the mountain.

If the detonating cord will split the blockage, using black powder added protected by rock powder extracted from the rock drill and hole flooding with water, will allow the Boulder of detached and stir from the main bank in the Sprint.

The primary block extraction method in these cave (Seccarezze) is using a special machine equipped with a diamond wire cutting the rock with a smooth, clean cut in this way the blocks obtained will not be solicited from the explosive that can trigger a process of fracturing.

The extracted blocks are delivered in firm ready for processing.


Steps followed by the author in collaboration with Patrizia Giagnotti.


Using mechanical means, blocks are placed in line with the diamond disc saw machine.

The diamond disk year different sizes depending on the block that you want to slice, vary from 50 cm in diameter up to 3.5 meters.

Sawing machine can also be multi disc, are also used diamond wire sawing machines to cut bad parts of the block.

Attractive and effective is the multi-blade chassis with which you can slice into a single solution the Luserna stone block, in order to fulfill this task the frame works tirelessly for four or five days without ever interrupting the sawing phase.


The Luserna Stone plates obtained by sawing are cleaned using a thermal process that heats up the surface, using torches to get natural stone.



This alternative processing is done with a special polishing machine that makes glossy sheets used for paving slabs subjected to polishing do not undergo the first trial of flaming.


This alternative route is run from the same machine that polishes simply changing the brushes.

Brushing makes the rough stone but smooth resulting in a sense of warmth.


Research, study and mineralogical investigation resulting in systematic sampling of the minerals of this place was only possible thanks to the hard work of excavators that have turned our applause for the outcome of the research.

Aeschynite in crystals, crystals in albite , anatase crystals, arsenopyrite crystals, Crystal bismutite , brookite crystals, calcite crystals, cerussite crystals, Crystal chalcopyrite , chlorite '' '' in cosalite crystals, crystals, epidote crystals, fluorite crystals, galena crystals, Hematite crystals, Crystal hellandite , heulandite crystals, ilmenite in laumontite crystals, crystals, magnetite , crystals marcasite crystals, molybdenite, Opal, pyrite crystals, Crystal quartz , rutile crystals, stilbite crystals, Crystal synchysite , titanite crystals, wulfenite crystals.



My heartfelt thanks to Istituto Geografico Militare in Florence that has made available the cartography of the area treated.

We thank Mr Vincenzo e Maurizio Maccagno, dealers Seccarezze quarries and Granite company holders St. Helens s.r.l.

We thank Bruno Marello.

Copyright 2022
Minerali Piemonte
Management by
Photos and descriptions edited by
Patrizia and Massimo Deidda