Fifty million years ago, the area of the Berici Hills was entirely submerged by water.
In this marine environment the Pietra Berica became a limestone of dual formation, clastic and biogenic, since it results both from the deposition of material transported from rivers to the sea, and from the sedimentation of skeletons of aquatic organisms as foraminifera and bivalves.

In those warm seas countless species of fish and clams lived, while the seabed was rich in corals and seaweeds.
The stone of the Berici Hills is also called soft stone, due to its easy workability and is classified into two distinct groups: the first one is called Pietra di Nanto and includes: the Nanto, the S. Germano, the Giallo Dorato, the Grigio Argento stone.
All these stones from the eocene, are dated to fifty-five million years ago and characterized by a straw-yellow or gray color, due to the presence of iron oxides in their chemical composition.

The second group of the Vicenza Stone is dated back to some millions of years later and includes the S. Gottardo and Bianco Avorio, characterized by the white color, due to the purity of the limestone mass.
The different training environment determines the salient features. The fossils in particular, contained in the stone itself, represent a sort of DNA: besides being an enrichment and natural decoration, they characterise the stone aging and classification.

The Pietra di Vicenza has been privileged since Roman times for its purity and strength.
It is therefore used to create architectural elements, sculpture of statues and decorative garden objects.
It owes its characteristics of weather resistance to the phenomenon of “carbonation”: the rain penetrates the stone and dissolves a part of limestone.
The water is naturally filtered, depositing and creating a layer of calcite which re-solidifies the stone, making it more solid, less porous and less affected by water and frost.

This quality of Vicenza Stone has been known since ancient times; tradition says, in fact, to work the stone when it has just been quarried before it hardens.
In the Pietra di Nanto these phenomenon does not occur that often, but not for this reason it is less suitable for external uses. It is also used as interior architectural stone for its intense yellow colour, for the construction of stoves and fireplaces, as the presence of silica in its chemical composition makes the stone refractory.

Historical references

In 1524 the young Andrea Palladio, is welcomed by the sculptors Giacomo da Porlezza and Girolamo Pittoni da Lumignano in their workshop.
They both were in contact with the greatest artists and architects of the time, active with sculptural works and architecture in the first half of the 16th century.
The young Palladio carries out his apprenticeship as a stonemason in Padua under the master Bortolomeo Cavazza da Sossano. He was committed to ornate drawing, engraving and sculpture of architectural elements.

This knowledge will serve him later, as mature architect, to devise projects in which Pietra Berica becomes a valuable material for the decoration and embellishment of the richest architectures such as stone bases, capitols, architraves, friezes, cornices, the contours of windows and doors, steps, floors, balustrades, shelves for jutting balconies.
The Roman construction technique was followed, where only the external covering was made of stone.

Palladio reports in his work The Four Books of Architecture: “The stones will be worked immediately quarried: because it will be easier to work them at the time. Indeed, for some reason, they become to harden after a while”. The reason for this will be explained only many centuries later.
Palladio also writes about the Roman bridges located in Vicenza: “They are made in Pietra di Costozza, which is a soft stone to be cut like the wood.”