# Istrian stone - Page: https://taslar.bumba.tr/en/stones/istrian-stone/ - Turkish: İstriya taşı - Also known as: Pietra d'Istria, Orsera stone (pietra di Orsera), Kirmenjak - Kind: Rock - Classification: Rocks › Sedimentary rocks › Chemical and biochemical - Hardness (Mohs): 3 - Specific gravity: 2.7–2.8 g/cm³ - Colours: salt white, light yellowish, ivory, pale grey (when weathered) - Composition: A dense, practically impermeable limestone: mostly calcium carbonate (calcite) derived from the shells and skeletons of sea creatures. Its most famous kind, Kirmenjak stone, formed from fine lime mud (carbonate mudstone) laid down in shallow coastal waters. - Texture: Very fine-grained and compact, with low porosity. Beds range from a few centimetres to more than a metre thick, and the stone is sometimes crossed by brownish or reddish veins. - Value ladder: 4/9 step, Fine dimension stone and ore The white stone Venice stands on: a dense, watertight Istrian limestone that went into the lagoon city's foundations, churches and bridges. Istrian stone is a white to pale yellowish limestone from the west coast of the Istrian peninsula, now in Croatia. It is very dense and absorbs almost no water. Venice, which had no stone of its own, shipped it in for centuries for its foundations, façades and bridges. Because it looks like marble when polished it is often called “marble”, but it is in fact a sedimentary rock. ## How does it form? Most of the rocks of the Istrian peninsula are limestones laid down beneath a warm, shallow sea in the Jurassic and Cretaceous periods. Calcium carbonate from the shells and skeletons of the creatures living in that sea settled as a fine lime mud, which hardened into rock over time. The most famous kind of Istrian stone, **Kirmenjak stone**, belongs to the Tithonian, the last stage of the Late Jurassic (about 150 million years ago). The rocks of the Kirmenjak quarry formed from lime mud settling on coastal flats that the tide alternately flooded and exposed. Because the mud dried out only briefly before being covered by fresh mud, even the footprints of the giant sauropod dinosaurs that walked across it were preserved. Its very fine grain and compact texture make the stone practically watertight. Older Italian sources date the stone from the coast between Vrsar (Orsera) and Poreč to the Early Cretaceous. Further south, around Pula, other Late Cretaceous limestones are quarried. ## What is it used for? - **The foundations and façades of Venice:** Venice, with no stone of its own, shipped in Istrian stone from at least the 13th century. Its buildings were set on plates of Istrian limestone laid on wooden piles driven into the lagoon mud, and the salt-resistant stone protected the brick walls above. The church of Santa Maria della Salute and the façade of San Zaccaria are among its best-known examples. - **Play of colour:** In Venetian architecture, white Istrian stone was set beside coloured stones such as red Verona stone. In 1580 Francesco Sansovino credited the stone with the city's distinctive look. - **Antiquity:** The Romans took building blocks and sarcophagus stone from Istria's coastal quarries. The one-piece dome of about 230 tonnes on the Mausoleum of Theodoric in Ravenna (AD 520) is held to be Istrian stone, although which quarry it came from is still debated. - **Towns of Istria and Dalmatia:** The stone also became the characteristic building material of the Venetian-ruled towns along the Adriatic coast. ## Where is it found? Istrian stone is quarried on the west coast of the Istrian peninsula in Croatia. The best-known deposit is the **Kirmenjak** quarry near Poreč. The quarries around **Vrsar** (Italian Orsera) were worked most intensively under Venetian rule (13th–18th centuries), which is why the stone is also called “pietra di Orsera”. The Valsaline and Sveta Eufemija quarries near **Rovinj** show traces of Roman working. Further south, the light cream limestone of the **Brijuni Islands** and the stone of the **Cave Romane** quarry near Pula were also used for centuries; the outer wall of Pula's Roman amphitheatre was built of stone from that quarry. ## How to recognise it - Freshly cut, it is salt white or pale yellowish; outdoors it turns pale grey over the years. - It is very fine-grained and compact, with hardly any visible pores, and soaks up almost no water. - In Venice it is seen in door and window frames, balustrades, steps and the base courses of buildings close to the waterline. - Being a limestone, it fizzes in dilute acid and can be scratched with a steel knife. ## What determines its value? As a building stone, its value depends on how little water it absorbs, how well it resists pressure and salt water, how white and even its colour is, and whether large, crack-free blocks can be quarried. Its reputation was made by centuries of standing up to the salty water of the Venetian lagoon. For repairing historic buildings, finding stone from the same quarries that matches in colour and texture matters too. This information is educational, not buying, selling or investment advice. Value varies enormously with quality and treatment. ## Myths and misconceptions - Myth: Istrian stone is a marble. Fact: It is often called “marble” because it looks like marble when polished, but that is not correct. Istrian stone is a limestone; marble is a metamorphic rock formed when limestone is transformed by heat and pressure. ## Curious questions **Why did Venice use Istrian stone?** Venice, in the middle of its lagoon, had no building stone nearby. Istrian stone could easily be brought across the sea, and because it is so dense it takes up almost no salt water. That is why the city's buildings were set on plates of Istrian limestone laid on top of wooden piles. ## Did you know? - In the Kirmenjak quarry, which gives Istrian stone its best-known name, almost a thousand sauropod footprints have been found in a single Late Jurassic layer. They are the oldest known evidence of dinosaurs on the Adriatic-Dinaridic carbonate platform. - Venice's church of Santa Maria della Salute stands on a platform resting on a million wooden piles and is built of Istrian stone and brick finished with marble dust. - The quarries of the Brijuni Islands supplied stone to Venice in the Middle Ages, and to Vienna and Berlin in Austro-Hungarian times. ## Where is it found? - Kirmenjak, near Poreč, Istria, Croatia (Type locality): Gives its name to the most famous kind of Istrian stone. Almost a thousand sauropod footprints have been found in the Late Jurassic (Tithonian) limestones of the quarry. - Vrsar (Orsera), Istria, Croatia (Historic source): Abandoned quarries of the stone known as “pietra di Orsera”, worked most intensively under Venetian rule (13th–18th centuries). The quarry on the islet of Sveti Juraj shows traces of Roman working. - Rovinj (Valsaline, Sveta Eufemija), Istria, Croatia (Historic source): Coastal quarries in Jurassic limestone with traces of Roman working; at Sveta Eufemija stone was cut for sarcophagi. - Poreč and the islet of Sveti Nikola, Istria, Croatia (Historic source): According to the Croatian archaeologist Ante Šonje, the one-piece dome of the Mausoleum of Theodoric in Ravenna was quarried on this islet; the view is debated. - Brijuni Islands, Istria, Croatia (Historic source): Light cream limestone from the islands' quarries went into the palaces and bridges of Venice in the Middle Ages, and to Vienna and Berlin in Austro-Hungarian times. The islands are now a national park. - Cave Romane quarry, Vinkuran, near Pula, Croatia (Known locality): The stone of the outer wall of the Roman amphitheatre in Pula came from this quarry; the Late Cretaceous limestone is still worked today. ## Sources - [Istrian stone](https://en.wikipedia.org/wiki/Istrian_stone), Wikipedia - [Stone as a resource in Istrian antiquity (K. Šprem), About Two Provinces, Hungarian Polis Studies 26](https://ffpu.unipu.hr/_download/repository/Sprem_2020._Stone_as_a_resource_in_Istrian_Antiquity.pdf), Eötvös Loránd University / University of Debrecen, 2020 - [Stable isotope analysis of Upper Tithonian limestones with dinosaur footprints from Kirmenjak quarry (Istria, Croatia) (Cvetko Tešović, Mezga, Glumac)](https://hrcak.srce.hr/24877), Geologia Croatica, 2008 - [Indagini chimico-petrografiche su calcari dell'Istria e su frammenti dei monoliti del Mausoleo di Teodorico (R. Mezzetti, R. Pirani)](https://ojs.zrc-sazu.si/av/article/download/9883/9039/27172), Arheološki vestnik (ZRC SAZU) - [Abandoned stone quarries (Vrsar)](https://www.istra.hr/en/experience/culture/cultural-sights/abandoned-stone-quarries), Istria Tourist Board - [Mausoleum of Theodoric](https://en.wikipedia.org/wiki/Mausoleum_of_Theodoric), Wikipedia - [Santa Maria della Salute](https://en.wikipedia.org/wiki/Santa_Maria_della_Salute), Wikipedia - [Venice](https://en.wikipedia.org/wiki/Venice), Wikipedia - [Kirmenjak](https://en.wikipedia.org/wiki/Kirmenjak), Wikipedia - [Vrsar](https://en.wikipedia.org/wiki/Vrsar), Wikipedia - [Rovinj](https://en.wikipedia.org/wiki/Rovinj), Wikipedia - [Poreč](https://en.wikipedia.org/wiki/Pore%C4%8D), Wikipedia - [Brijuni](https://en.wikipedia.org/wiki/Brijuni), Wikipedia - [Vinkuran](https://en.wikipedia.org/wiki/Vinkuran), Wikipedia - [Densities of Solids](https://www.engineeringtoolbox.com/density-solids-d_1265.html), The Engineering ToolBox - [Limestone](https://geology.com/rocks/limestone.shtml), Geology.com Source: https://taslar.bumba.tr/en/stones/istrian-stone/ · Licence: CC BY-SA 4.0