Poros stone is a lightweight, soft,

marl Marl is an earthy material rich in carbonate minerals, clays, and silt. When hardened into rock, this becomes marlstone. It is formed in marine or freshwater environments, often through the activities of algae. Marl makes up the lower part o ...

limestone Limestone ( calcium carbonate ) is a type of carbonate sedimentary rock which is the main source of the material lime. It is composed mostly of the minerals calcite and aragonite, which are different crystal forms of . Limestone forms whe ...

that was widely used in construction and statues of

Ancient Greece Ancient Greece ( el, Ἑλλάς, Hellás) was a northeastern Mediterranean civilization, existing from the Greek Dark Ages of the 12th–9th centuries BC to the end of classical antiquity ( AD 600), that comprised a loose collection of cult ...

. There is no precise definition of the term, although its roots go to

antiquity Antiquity or Antiquities may refer to: Historical objects or periods Artifacts *Antiquities, objects or artifacts surviving from ancient cultures Eras Any period before the European Middle Ages (5th to 15th centuries) but still within the histo ...

, when it was used to designate any porous building rock, regardless of its origin, mostly in contrast with

marble Marble is a metamorphic rock composed of recrystallized carbonate minerals, most commonly calcite or Dolomite (mineral), dolomite. Marble is typically not Foliation (geology), foliated (layered), although there are exceptions. In geology, the ...

. In the 20th century the archeologists continued to use the term in the similarly loose way: " asmade to include almost all light-coloured stones" that were not definitely marble or hard limestone. The stone is one of the chief formations of the

Neogene The Neogene ( ), informally Upper Tertiary or Late Tertiary, is a geologic period and system that spans 20.45 million years from the end of the Paleogene Period million years ago ( Mya) to the beginning of the present Quaternary Period Mya. ...

(

Miocene The Miocene ( ) is the first geological epoch of the Neogene Period and extends from about (Ma). The Miocene was named by Scottish geologist Charles Lyell; the name comes from the Greek words (', "less") and (', "new") and means "less recen ...

Pliocene The Pliocene ( ; also Pleiocene) is the epoch in the geologic time scale that extends from 5.333 million to 2.58Peloponnese The Peloponnese (), Peloponnesus (; el, Πελοπόννησος, Pelopónnēsos,(), or Morea is a peninsula and geographic regions of Greece, geographic region in southern Greece. It is connected to the central part of the country by the Isthmu ...

, making a common construction stone there. Even when hardened by exposure to the elements, is much more readily cut with a knife than is an ordinary limestone. The ease of working with is the reason for its extensive use as a building stone, especially for foundations and other architectonic parts that are not exposed to view.

Ancient term

The Greek geographer

Pausanius Pausanias ( /pɔːˈseɪniəs/; grc-gre, Παυσανίας; c. 110 – c. 180) was a Greek traveler and geographer of the second century AD. He is famous for his ''Description of Greece'' (, ), a lengthy work that describes ancient Greece ...

uses the term "" to describe the material of the

Temple of Zeus at Olympia The Temple of Zeus at Olympia was an ancient Greek temple in Olympia, Greece, dedicated to the god Zeus. The temple, built in the second quarter of the fifth century BC, was the very model of the fully developed classical Greek temple of the Dor ...

, which was built of local shell limestone,

Theophrastus Theophrastus (; grc-gre, Θεόφραστος ; c. 371c. 287 BC), a Greek philosopher and the successor to Aristotle in the Peripatetic school. He was a native of Eresos in Lesbos.Gavin Hardy and Laurence Totelin, ''Ancient Botany'', Routledge ...

(and

Pliny the Elder Gaius Plinius Secundus (AD 23/2479), called Pliny the Elder (), was a Roman author, naturalist and natural philosopher, and naval and army commander of the early Roman Empire, and a friend of the emperor Vespasian. He wrote the encyclopedic '' ...

, who borrows the description) declares it to be a less dense variant of

Parian marble Parian marble is a fine-grained semi translucent pure-white and entirely flawless marble quarried during the classical era on the Greek island of Paros in the Aegean Sea. It was highly prized by ancient Greeks for making sculptures. Some of the ...

Herodotus Herodotus ( ; grc, , }; BC) was an ancient Greek historian and geographer from the Greek city of Halicarnassus, part of the Persian Empire (now Bodrum, Turkey) and a later citizen of Thurii in modern Calabria ( Italy). He is known f ...

also contrasts coarse with fine marble.

Archeological term

Henry Stephens Washington Henry Stephens Washington (January 15, 1867 – January 7, 1934) was an American geologist. Biography Washington was born in Newark, New Jersey on January 15, 1867. He attended Yale University, graduating in 1886, and took his masters there two y ...

geologist A geologist is a scientist who studies the solid, liquid, and gaseous matter that constitutes Earth and other terrestrial planets, as well as the processes that shape them. Geologists usually study geology, earth science, or geophysics, althou ...

with a major interest in

classical studies Classics or classical studies is the study of classical antiquity. In the Western world, classics traditionally refers to the study of Classical Greek and Roman literature and their related original languages, Ancient Greek and Latin. Classics ...

) declared in 1923: Washington describes the differences between and regular limestone as the former being very finely

arenaceous Arenite (Latin: ''arena'', "sand") is a sedimentary clastic rock with sand grain size between 0.0625 mm (0.00246 in) and 2 mm (0.08 in) and contain less than 15% matrix. The related adjective is ''arenaceous''. The equivalent G ...

y; most often of a pale cream color, also light yellow or light gray; somewhat granular but rather soft and

friable Friability ( ), the condition of being friable, describes the tendency of a solid substance to break into smaller pieces under duress or contact, especially by rubbing. The opposite of friable is indurate. Substances that are designated hazardous, ...

and easily cut with a knife, especially when first exposed in the quarry (similar to the

volcanic tuff Tuff is a type of rock made of volcanic ash ejected from a vent during a volcanic eruption. Following ejection and deposition, the ash is lithified into a solid rock. Rock that contains greater than 75% ash is considered tuff, while rock cont ...

s of

Roman Campagna The Roman Campagna () is a low-lying area surrounding Rome in the Lazio region of central Italy, with an area of approximately . It is bordered by the Tolfa and Sabatini mountains to the north, the Alban Hills to the southeast, and the Tyrrhenia ...

in this last quality, while having nothing in common otherwise). Hadjidakis et al., while reviewing the ancient quarries, use the term in its ancient sense, to designate any low-density rock, regardless of its petrographical classification.

References

Sources

* * * * {{cite book , last=Frazer , first=J.G. , title=Pausanias's Description of Greece , publisher=Macmillan and Company, limited , issue=v. 3 , year=1913 , url=https://books.google.com/books?id=NcPNAAAAMAAJ&pg=PA503 , access-date=2023-09-18 Ancient Greece Building stone Limestone