The “pera cunca” is one of the best-known altar-blocks in the Canavese area. With this name they designate stones bearing more or less deep cavities, connected to each other by channels, which could in some way have been used for sacrificial rites.
Generally these boulders cannot be dated, and if they are, they may belong to cultures that have few points in common with the Celtic one; moreover, there is abundant evidence of how the generically "pagan" rites were practiced well into the Christian age. The revelation of the presence of this boulder was made around 1920 to the Superintendent of that time and was defined, in the following years, a "boulder-altar". The channeled cupels and the central basin are well suited to cults that envisage libations on sacred altar-shaped stones, repeatedly described by chroniclers of the Roman age referring to pre-existing indigenous peoples in Northern Italy. However, it is necessary to move with caution on such classic information, since without archaeological evidence it can be easy to reach hasty or erroneous conclusions.
The stone, an erratic boulder, had already been known for some time and was traditionally called by the inhabitants "Pera Cunca" or "Pietra Conca or Concava". It is located on the southernmost slopes of the morainic Amphitheater of Ivrea among the last hills that testify to the maximum extension to the south of the glacial tongue. It is likely that the latter is responsible for the local presence of the stone, which deposited it when the glacier began to retreat.