Stone appears to be still, unchangeable, untouched by the tribulations of living beings.
Being outside of time, it always pointed back to the concept fo Creation.
Nestled, inaccessible, closed inside the natural chest of rock, those anomalies we called treasures lie waiting to be discovered: minerals of the strangest shape, unexpected colors, otherworldly transparency.
Upon breaking a stone, some designs may be uncovered which seem to be a work of intellect. One could recognize panoramas, human figures, cities, plants, cliffs, ocean waves.

Who is the artist that hides these fantasies inside the rock? Are they created by God’s hand? Or were these visions and landscapes dreamed by the stone itself, and engraved in its heart?

If during the Middle Ages these stone motifs were probably seen as an evidence of the anima mundi, at the beginning of the modern period they had already been relegated to the status of simple curiosities.
XVI and XVII Century naturalists, in their wunderkammern and in books devoted to the wonders of the world, classified the pictures discovered in stone as “jokes of Nature” (lusus naturæ). In fact, Roger Caillois writes (La scrittura delle pietre, Marietti, 1986):

The erudite scholars, Aldrovandi and Kircher among others, divided these wonders into genres and species according to the image they saw in them: Moors, bishops, shrimps or water streams, faces, plants, dogs or even fish, tortoises, dragons, skulls, crucifixes, anything a fervid imagination could recognize and identify. In reality there is no being, monster, monument, event or spectacle of nature, of history, of fairy tales or dreams, nothing that an enchanted gaze couldn’t see inside the spots, designs and profiles of these stones.

It is curious to note, incidentally, that these “caprices” were brought up many times during the long debate regarding the mystery of fossils. Leonardo Da Vinci had already guessed that sea creatures found petrified on mountain tops could be remnants of living organisms, but in the following centuries fossils came to be thought of as mere whims of Nature: if stone was able to reproduce a city skyline, it could well create imitations of seashells or living things. Only by the half of XVIII Century fossils were no longer considered lusus naturæ.

Among all kinds of pierre à images (“image stones”), there was one in which the miracle most often recurred. A specific kind of marble, found near Florence, was called pietra paesina (“landscape stone”, or “ruin marble”) because its veinings looked like landscapes and silhouettes of ruined cities. Maybe the fact that quarries of this particular marble were located in Tuscany was the reason why the first school of stone painting was established at the court of Medici Family; other workshops specializing in this minor genre arose in Rome, in France and the Netherlands.

Aside from the pietra paesina, which was perfect for conjuring marine landscapes or rugged desolation, other kinds of stone were used, such as alabaster (for celestial and angelic suggestions) and basanite, used to depict night views or to represent a burning city.

Perhaps it all started with Sebastiano del Piombo‘s experiments with oil on stone, which had the intent of creating paintings that would last as long as sculptures; but actually the colors did not pass the test of time on polished slates, and this technique proved to be far from eternal. Sebastiano del Piombo, who was interested in a refined and formally strict research, abandoned the practice, but the method had an unexpected success within the field of painted oddities — thanks to a “taste for rarities, for bizarre artifices, for the ambiguous, playful interchange of art and nature that was highly appreciated both during XVI Century Mannerism and the baroque period” (A. Pinelli on Repubblica, January 22, 2001).

Therefore many renowned painters (Jacques Stella, Stefano della Bella, Alessandro Turchi also known as l’Orbetto, Cornelis van Poelemburgh), began to use the veinings of the stone to produce painted curios, in tension between naturalia e artificialia.

Following the inspiration offered by the marble scenery, they added human figures, ships, trees and other details to the picture. Sometimes little was needed: it was enough to paint a small balcony, the outline of a door or a window, and the shape of a city immediately gained an outstanding realism.

Johann König, Matieu Dubus, Antonio Carracci and others used in this way the ribbon-like ornaments and profound brightness of the agate, the coils and curves of alabaster. In pious subjects, the painter drew the mystery of a milky supernatural flare from the deep, translucent hues; or, if he wanted to depict a Red Sea scene, he just had to crowd the vortex of waves, already suggested by the veinings of the stone, with frightened victims.

Especially well-versed in this eccentric genre, which between the XVI and XVIII Century was the object of extended trade, was Filippo Napoletano.
In 1619 the painter offered to Cosimo II de’ Medici seven stories of Saints painted on “polished stoned called alberese“, and some of his works still retain a powerful quality, on the account of their innovative composition and a vivid expressive intensity.
His extraordinary depiction of the Temptations of Saint Anthony, for instance, is a “little masterpiece [where] the artist’s intervention is minimal, and the Saint’s entire spiritual drama finds its echo in the melancholy of a landscape of Dantesque tone” (P. Gaglianò on ExibArt, December 11, 2000).

The charm of a stone that “mimicks” reality, giving the illusion of a secret theater, is unaltered still today, as Cailliois elegantly explains:

Such simulacra, hidden on the inside for a long time, appear when the stones are broken and polished. To an eager imagination, they evoke immortal miniature models of beings and things. Surely, chance alone is at the origin of the prodigy. All similarities are after all vague, uncertain, sometimes far from truth, decidedly gratuitous. But as soon as they are perceived, they become tyrannical and they offer more than they promised. Anyone who knows how to observe them, relentlessly discovers new details completing the alleged analogy. These kinds of images can miniaturize for the benefit of the person involved every object in the world, they always provide him with a copy which he can hold in his hand, position as he wishes, or stash inside a cabinet. […] He who possesses such a wonder, produced, extracted and fallen into his hands by an extraordinary series of coincidences, happily imagines that it could not have come to him without a special intervention of Fate.

Still, unchangeable, untouched by the tribulations of living beings: it is perhaps appropriate that when stones dream, they give birth to these abstract, metaphysical landscapes, endowed with a beauty as alien as the beauty of rock itself.

Several artworks from the Medici collections are visible in a wonderful and little-known museum in Florence, the Opificio delle Pietre Dure.
The best photographic book on the subject is the catalogue Bizzarrie di pietre dipinte (2000), curate by M. Chiarini and C. Acidini Luchinat.