Geology of Building Stones
This slide show presents a brief outline of the geologic history of some of the common types of building stone.
Types of Building Stone
Most building stones fall into the catagories of sandstones, limestones, granites, slates, quartzites and fieldstones.
Geologic Time Scale
The Earth is about 4.6 billion years old. Igneous rocks range from 30 million to over 2 billion years old. Metamorphic rocks are mostly older than 500 million years. Most sedimentary rocks formed in the last 500 million years of this time.
Sedimentary Rocks
Sedimentary rock is formed when mineral and rock grains are deposited and compressed (sandstones) and from minerals that precipitate from solution (limestones). Most sedimentary rocks were deposited in the ocean although some building sandstones are non-marine deposits.
Igneous Rocks
Igneous rock is formed by magma or lava (molten rock) being cooled and becoming solid.
Metamorphic Rocks
Metamorphic rocks are formed when pre-existing rocks are heated, compressed and deformed deep beneath the surface of the earth.
Igneous, metamorhic and sedimentary rock formation
Igneous, metamorphic and sedimentary rocks form under different conditions, usually in separate parts of a continent.
Sandstones
Sandstone is composed of sand-sized mineral or rock grains. Most sandstone is composed of quartz and/or feldspar because these are the most common minerals in the crust of the Earth.
Bluestone deposits in North America
Bluestone is a sandstone that has been quarried for centuries in Pennsylvania and New York. It was deposited as part of the Catskill Delta in which sediment was shed westward from the rising Acadian (ancient Appalacian) Mountains during Devonian time.
Bluestone quarry in northeast Pennsylvania
Blocks are removed from the bluestone quarry and then processed into finished products.
Bluestone Products
Bluestone is most commonly used as a paving stone. It ranges in color from blue to olive green and brown.
Brownstone used in New York City
Brownstone is a brown sandstone which was quarried intensively in the 18th and 19th centuries and was widely used in New York City as well as other cities in the eastern U.S.
Brownstone deposits in North America
Brownstone was deposited in rift valleys that formed as the North American plate separated from the African plate during the Triassic period.
Diagram of continental rifting
Brownstone deposits were formed when erosion filled portions of the developing continental rift with sandstone.
Brownstone quarry in Connecticut
Brownstone is only quarried now on a small scale in Connecticut. Brownstone quarrying was a much larger industry in the 19th and early 20th century. Most of the quarries were flooded during a hurricane in 1938 and never reopened.
North American ~85 million years ago
Thick deposits of Cretaceous-age sandstone were shed eastward from the rising Rocky Mountains into a seaway that covered the central western U.S.
Cliff Palace at Mesa Verde Nation Park
Cretaceous sandstones have been used for centuries in North America and are still quarried today in several places in the western U.S.
Limestone terrace walls in Mallorca, Spain
Limestone, dolomite, travertine and marble are related rocks formed from a parent rock composed primarily of calcium carbonate. The are called carbonate rocks.
Carbonate rocks
Limestone, dolomite, travertine and marble are called carbonate rocks because they contain calcium and magnesium carbonate.
Limestone quarry in Minnesota, U.S.
Limestones are typically quarried in blocks which are then processed into finished products. In this image, a driller is outlining blocks that will later be broken out of the ground.
Dolomite Mountains, Italy
Dolomites are quarried in many places around the world but gets its name from the Dolomite Mountains in Italy.
Roman Colosseum, Rome, Italy
Travertine is limestone that precipitates at hot water springs. It is quarried in many places throughout the world. Travertine was quarried near Tivoli, Italy and used by the Romans to build the colosseum, aquaducts, and many other ancient structures.
The Parthenon in Athens, Greece
The Parthenon in Greece was built from Pentelic Marble quarried on Mount Pentelikos near Athens, Greece. The famous Elgin Marbles were part of the Parthenon and are, at least for now, in the British Museum in London.
Marble quarry in Carrara, Italy
Marble has been quarried near Carrara, Italy for millenia. Many of the most famous historical structures and statues in Italy, including Michelangelo\'s David used Carrara marble because of its consistency in color and texture.
Marble quarry in Carrara, Italy
Carrara Marble is quarried in large blocks which are then processed into finished products and shipped around the world.
Granite domes in Yosemite National Park, U.S.
In the stone industry, the term granite is used for any crystalline igneous or metamorphic rock. Granites are typically the hardest, most durable building stones.
Rock of Ages quarry in Barre, Vermont, U.S.
Granites are quarried throughout the world, particularly now in China and India. It has been quarried in Barre, Vermont in the U.S. since the early 19th century.
Granite Colors
Granites range in color from nearly white to black. The color depends on the types of minerals that make up the granite.
Slate quarry in Vermont, U.S.
Slate is a metamorphic rock that formed by heating and compressing shale. It splits into thin sheets that can be used for paving or roofing tiles. It is quarried in the eastern U.S. as well as Europe and Asia.
Sorting slate tiles at the Penrhyn quarry, Wales
The famous Penrhyn slate quarries in Wales have been in operation for centuries. These quarries have great historical significance in the British Isles.
Slate roofing on an ancient Irish barn
The majority of quarried slate has been used for roofing tiles although it has been produced for paving and other uses.
Fieldstone barn in County Tipperary, Ireland
Fieldstones are any type of loose stone that can be collected at or near the surface of the Earth.
Extent of glaciers in North America
The glaciers that covered much of North American and Europe left extensive fieldstone deposits in their wake.
Fieldstone mill in Pennsylvania, U.S.
Many colonial-era buildings in the northeastern United States were built from glacial fieldstones.
Fieldstone wall in County Tipperary, Ireland
Fieldstones were also used for countless small and large structures in Ireland and England.
The End
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