PROCESSING OF GREEN SOAPSTONE PIRLO: THE CLORITOSCISTO
Studies done by the middle of the twentieth century by Enrico Besta Valtellina and other study on archaeological soapstone found after excavations occurred in Tresivio (pins, fusaruoli, bobbins and debris washing unmistakable signs of lathe machining obtained by Stone Valmalenco) it is probable that the activity date back to prehistoric Iron Age. Already in the first century A. D. the naturalist Pliny the Elder mentions the manufacture of pots made on a lathe with a green stone Como, named to a national resonance Como being the capital of the Curia, which included and still includes the Valtellina. The process was certainly started in Valchiavenna, but followed closely by Valmalenco if we consider the 40 quarries and 50 lathes existed along streams Mallero, Giumellini Sassersa and above all, the craftsmen involved in this work could be about a hundred. From death records starting from the end of the seventeenth century, are the only workers to be skilled craftsmen: Soapstone quarry workers and laveggiai. In winter groundwater extracted from the quarry the stone from the rock with pickaxes double pointed that "asisc" truncated cone-shaped block that block is called "ciapùn", managing to get a piece from the same set of pans called "leveche "starting from the largest to smallest, dividing them from each other, carving the first vertical part" spunda ", then the fund is the most sensitive, with a special hooked tool called" sudùn. After turning, the "leveche" was armed with a metal hoop to be able to handle, run mainly by tinsmiths Lanzada "blacksmith" who thought to marketing. Alpine valleys the use of this soft stone was quite normal because in the absence of the metal was needed to construct heat-resistant containers and storage containers, useful for domestic needs. Even today, thanks to the structural formation of the stone, "leveche" is researched and has excellent culinary properties that can not occur in other artifacts of modern technology. In particular, lends itself to cook stews, casseroles, stews, game, psalms, fondues, soups and tripe, while maintaining the organoleptic properties of foods. Ollie is a technical name given to the Roman Empire all the stones to keep from turning to easy which are obtained pots and containers of food and oil, called "jars" from which the name "soap". The stone is a variety of serpentine and is predominantly magnesium silicate, is divided into two main groups: talcoscisto and cloritoscisto. We differ in their crystalline structure, lamellar, granular, hardness and color. The greyish white, which has as its main component talc, talcoscisto is found in abundance along the Italian Alps, used in 30 areas, including in the town of Valbrutta Lanzada in Valmalenco. Cloritoscisto the other hand, is much more rare and valuable: the main component is the chlorine which gives the typical green color is also found in four areas of Piedmont, but the trend is more important in Valmalenco tapped by as many as 40 quarries, two of which are still active . The cloritosciti are the result of metamorphic transformations on basic trends in the large cluster that gave rise to ultrabasic serpentinites. Under the name of Soapstone Green Pirlo, cloritoscito of the Church for the main component chlorite, present for more than 95% in the form of a thick felt of small green leaf, leaving voids that intersect to form a solid rock of high potential heat.
2. The analysis
Microscopic examination performed by the University of Rome by prof. Mottana, notes in particular that the blades overlap in two directions perpendicular to each other, so the schistosity is not very pronounced. The X-ray analysis determined that chlorite and Turing, a variety of ferrifera Chamoso has composition (Fe11, 92 Mg0, 08) 12 (Al2, SI5 12, 88) 8 O20 (OH) 16. More recent analysis (by Bedoya, Montrasio, Scesa, 1993), qualify the chlorite that makes up the soapstone as a variety of ferrifera clinocloro (ripidolite).
3. The current mining and processing
From 1960 onwards, no more stone was quarried by hand, but with compressed air drills using a linear continuity of holes. Currently, the extraction is done using helical wire as conductor of silica sand that runs on a series of pulleys to cut the stone in controvena abrasions, then removed with ease along the schistosity. As noted are the only underground quarries in Italy to use this ingenious method. Now the mechanics are back, certainly not typical, but the working method remains the same as the old man's tools are handled in the same love from turner that the result of the work depends solely on his ability. From a purely work related to the function of the domestic kitchen, the beginning of the current century the production of furniture tentatively extended to objects: candlesticks, vases, candy boxes, ashtrays, smoking services, tea, coffee, etc. . After the 30s turned the objects were decorated with engraved or decorated in relief with ever more sophisticated tastes and, up to the production of objects and sculptures of real artistic value. All of these rural activities and craft are part of that heritage Malence ethnographic built over the centuries by people Malenco according to the survival and development in balance between man and environment.
4. Characteristics and use of the "leveche"
Thanks to its excellent thermal properties, soapstone is one of the few natural stones suitable for storing foods to cook. The "leveche" pan heats slowly and reached the desired temperature remains constant with a very small source of heat, baking the food without sticking to the bottom. Removed from the heat cools down equally slowly in prolonged heat food. Leftovers can remain in the pot for a few days and be heated without losing the flavor and organoleptic substances. The "foragn" container allows you to store foods long as cheeses, meats, seasonings and other ingredients, spices, flavorings, salt, tobacco, etc.. It was simply the refrigerator of our grandparents.
5. Instructions for using the pot "leveche"
For proper use: 1. Grease the pan well inside and out with butter or fat or oil and let it soak well for two or three days 2. To prevent cracks due to uneven expansion, you should cook for the first time, stews or boiled with a wood fire or by placing the pan in oven. After that you can safely use the "leveche" Even with gas or other heat source fixed, using the retina or a cast iron plate spargifiamma. After these initial precautions the pot will be able to cook any kind of food that could break without fear. Important: Avoid thermal shock, never pour cold water into hot pan. To clean: wash like any other pot with soap flakes or liquid soap used for the simple dishes.