The general name potstone (pietra ollare) is given to different types of medium-fine grained rocks, particularly suited to the carving or turning of pots and bowls (olle). Petrographic analysis of Valchiavenna?s deposits has attributed its stone types to the talco- and chloroscists group, being identified by the naked eye for its grey or greeny-greyish colour. Potstone ltas good refractory qualities, being resistant to extremes o f temperature and maintaining gradually acquired heat for long periods.
Cooking pots made out of it do not absorb food nor add any taste. These products are typical o f alpine material culture, having been a distinctive continuous element since the laic Iron Age.
In this valley the extraction of potstone for making conking puts (laveggi) continued until towards the middle of last century, where it became economically njo longer worthwhile.
The main centres of production were Piuro and Chiavenna. Many quarries, in rock walls or slopes and in caves or narrow tunnels (trone), are to be found throughout the Park.
Skilled workers extracted the stone: the blocks to be cut and turned were already partially carved within the rock wall. Traces of this technique Can still clearly be seen today. Potstone was also quarried for the architectural elements, fountains, statues, friezes and noble coats of arms that characterize and decorate so many works in the area of Chiavenna.

Production contunued without interruption for centuries; as can be seen from Roman finds, the impressive 12 th century Baptistry of Chiavemra and the 15 th-19th century dates carved in the quarry walls. Alter this the work of extraction was gradually abandoned.

Lavéec and piòta
The Piòta
The piòta is a stone slab of a variety of gneiss, serpentine or slate, usually rectangular-shaped , used in the cooking of different kind of food on flame or on barbecue. T
his kind of cooking doesn´t require almost any dressing, indeed the food itself, while cooking, releases excess fat increasing its natural taste, at the same time the nutrition content is the same, intensifing spices and aroma use.

The lavéec
The "laveggio" (called in dialect "lavéec") is a container made of turned potstone.
Once it was used for cooking all kind of food, especially boiled; now it´s particularly used to cook spare-rib or game.
It´s said its strong points are the fast cooking, the maintenance of cooked food taste, the infrangibility of the pot, and, in the past , even the neutralization of any poison.