According to records, Lorenzo Mazzanga, barghigiano, prefetto del L’Orto Botanico dell’Università di Pisa from 1583 to 1592 discovered the diaspro – Jasper, the pietra dura of great aesthetic value to be found at the quarry at Giuncheto just outside Barga.
Greatly sought after and appreciated by Francesco, Grand Duke from 1574 to 1587, Barga diaspro was used in great quantities, from 1604 throughout the 17th century, in Florence, in places including the Chapel of the Princes, in the Church of San Lorenzo.
Since then those Barga quarries have fallen into disuse and become almost hidden from view.
Recently a visitor from Austria, Heinz Bieler was in the area searching for signs of those ancient quarries and their famous red rocks.
With help from local guides: Emilio Lammari, Raffaello Lammari and Ron Gauld, the Diaspora of Barga was once again brought out into the light.
Heinz Bieler has been researching and discovering rocks from all across Europe to add to his collection of over 400 different types of coloured stone.
He uses a technique of sculpting the rocks into a round ball, which is then ground down into a perfect sphere of around 8 cms diameter. Some of those spheres can be seen here in his gallery
Jasper (Diaspro) , an aggregate of microgranular quartz and/or chalcedony and other mineral phases,is an opaque, impure variety of silica, usually red, yellow, brown or green in color; and rarely blue. The common red color is due to iron inclusions. The mineral aggregate breaks with a smooth surface and is used for ornamentation or as a gemstone. It can be highly polished and is used for vases, seals, and snuff boxes. Jasper is known to have been a favorite gem in the ancient world; its name can be traced back in Arabic, Azerbaijani, Persian, Hebrew, Assyrian, Greek and Latin.
Diaspro di Barga, from Barga, Lucca, Tuscany, Italy – Geological description: Milky white chalcedony with aggregates of red hematitic inclusions is cut by a rhombohedral network of fine calcite-filled fractures. Later chalcedony/colourless quartz replaces and is coloured by orange brown siderite. Secondary fractures are more sinuous and random. Dark brown areas are filler/polishing compound.
Jervis (1881) describes the precise locality, geological context, and the famous use of the Barga jasper in the chapel of the Princes in the Church of San Lorenzo in Florence. – source – Oxford University Museum of Natural HistoryDiaspro di Barga. Purplish ground with gleaming white veins. The columns in the Borghese Chapel in S. Maria Maggiore are veneered with this stone. (Very rare).