The Flickr Pyritization Image Generatr

Heterophrentis sp. - pyritized fossil rugose coral from the Devonian of Ohio, USA.

This is a fossil solitary rugose coral, commonly known as a "horn coral". Rugosans are an extinct group - they only occur in Paleozoic rocks. The soft parts were sea anemone-like creatures called polyps. The polyps made calcareous hard-part skeletons. Most rugosans were solitary, but some were colonial.

The coral's skeleton is now composed of pyrite ("fool's gold" - FeS2, iron sulfide), a preservation style referred to as replacement. The specimen comes from the Middle Devonian Silica Formation (also known as the Silica Shale) in northwestern Ohio. Pyritized fossils are relatively common in the unit - pyrite can replace hard parts or it can be a coarsely-crystalline coating atop calcareous shells.

The most common fossil replacement minerals are quartz, pyrite, and apatite. Quartz is SiO2 (silica) - fossils that have been quartz-replaced are said to be silicified (silicification). Many silicified fossils have rounded to pustulose structures covering their surfaces. These are called beekite rings, but they're composed of ordinary quartz. Replacement by apatite (calcium phosphate) is called phosphatization.

Other minerals have also been found replacing minerals - many are quite rare. Reported fossil replacement minerals include: anglesite, apatite, barite, calamine, calcite, cassiterite, celestite, cerargyrite, cerussite, chalcocite, cinnabar, copper, dolomite, fluorite, galena, garnet, glauconite, gumbelite, gypsum, hematite, kaolinite, limonite, magnesite, malachite, marcasite, margarite, opal, pyrite, romanechite/psilomelane, siderite, quartz, silver, smithsonite, specular hematite, sphalerite, sulfur, uranium minerals, and vivianite.
(List mostly from info. in Hartzell, 1906 and Klein & Hurlbut, 1985)

Classification: Animalia, Cnidaria, Anthozoa, Rugosa, Stauriida, Streptelasmatidae

Stratigraphy: Silica Formation, Givetian Stage, upper Middle Devonian

Locality: unrecorded / undisclosed quarry in the Sylvania area, far-northern Lucas County, northwestern Ohio, USA

Heterophrentis sp. - pyritized fossil rugose coral from the Devonian of Ohio, USA.

This is a fossil solitary rugose coral, commonly known as a "horn coral". Rugosans are an extinct group - they only occur in Paleozoic rocks. The soft parts were sea anemone-like creatures called polyps. The polyps made calcareous hard-part skeletons. Most rugosans were solitary, but some were colonial.

The coral's skeleton is now composed of pyrite ("fool's gold" - FeS2, iron sulfide), a preservation style referred to as replacement. The specimen comes from the Middle Devonian Silica Formation (also known as the Silica Shale) in northwestern Ohio. Pyritized fossils are relatively common in the unit - pyrite can replace hard parts or it can be a coarsely-crystalline coating atop calcareous shells.

The most common fossil replacement minerals are quartz, pyrite, and apatite. Quartz is SiO2 (silica) - fossils that have been quartz-replaced are said to be silicified (silicification). Many silicified fossils have rounded to pustulose structures covering their surfaces. These are called beekite rings, but they're composed of ordinary quartz. Replacement by apatite (calcium phosphate) is called phosphatization.

Other minerals have also been found replacing minerals - many are quite rare. Reported fossil replacement minerals include: anglesite, apatite, barite, calamine, calcite, cassiterite, celestite, cerargyrite, cerussite, chalcocite, cinnabar, copper, dolomite, fluorite, galena, garnet, glauconite, gumbelite, gypsum, hematite, kaolinite, limonite, magnesite, malachite, marcasite, margarite, opal, pyrite, romanechite/psilomelane, siderite, quartz, silver, smithsonite, specular hematite, sphalerite, sulfur, uranium minerals, and vivianite.
(List mostly from info. in Hartzell, 1906 and Klein & Hurlbut, 1985)

Classification: Animalia, Cnidaria, Anthozoa, Rugosa, Stauriida, Streptelasmatidae

Stratigraphy: Silica Formation, Givetian Stage, upper Middle Devonian

Locality: unrecorded / undisclosed quarry in the Sylvania area, far-northern Lucas County, northwestern Ohio, USA

Paraspirifer bownockeri Stewart, 1927 - pyritized fossil brachiopod from the Devonian of Ohio, USA (view of ventral valve, with a cut window showing internal anatomy)

Brachiopods are sessile, benthic, filter-feeding, marine invertebrates. They first appear in Cambrian rocks and were abundant in Earth's oceans throughout the Paleozoic. They were also common in Mesozoic oceans, but are scarce in modern oceanic biotas. Brachiopods have two shells, called valves, that are usually calcareous (made of calcite - CaCO3 - calcium carbonate). Each shell of a brachiopod is bilaterally symmetrical, unlike each shell of a bivalve (clam).

This fossil brachiopod's shell is now composed of pyrite ("fool's gold" - FeS2, iron sulfide), a preservation style referred to as replacement. The specimen comes from the Middle Devonian Silica Formation (also known as the Silica Shale) in northwestern Ohio. Pyritized fossils are relatively common in the unit - pyrite can replace shells or it can be a coarsely-crystalline coating atop the calcareous shells. Remarkably, this brachiopod's spiral brachidium is visible through the window cut into the shell - the brachidium has been completely pyrizited. In spiriferid brachiopods, the brachidium is an internal, calcified support structure for the lophophore, which is the brachiopod's filter feeding apparatus.

The most common fossil replacement minerals are quartz, pyrite, and apatite. Quartz is SiO2 (silica) - fossils that have been quartz-replaced are said to be silicified (silicification). Many silicified fossils have rounded to pustulose structures covering their surfaces. These are called beekite rings, but they're composed of ordinary quartz. Replacement by apatite (calcium phosphate) is called phosphatization.

Other minerals have also been found replacing minerals - many are quite rare. Reported fossil replacement minerals include: anglesite, apatite, barite, calamine, calcite, cassiterite, celestite, cerargyrite, cerussite, chalcocite, cinnabar, copper, dolomite, fluorite, galena, garnet, glauconite, gumbelite, gypsum, hematite, kaolinite, limonite, magnesite, malachite, marcasite, margarite, opal, pyrite, romanechite/psilomelane, siderite, silica/quartz, silver, smithsonite, specular hematite, sphalerite, sulfur, uranium minerals, and vivianite.
(List mostly from info. in Hartzell, 1906 and Klein & Hurlbut, 1985)

Classification: Animalia, Brachiopoda, Articulata (a.k.a. Rhynchonelliformea), Spiriferida, Hysterolitidae

Stratigraphy: Silica Formation, Givetian Stage, upper Middle Devonian

Locality: unrecorded / undisclosed, but likely from a quarry in northwestern Ohio, USA

Paraspirifer bownockeri Stewart, 1927 - pyritized fossil brachiopod from the Devonian of Ohio, USA (view of ventral valve, with a cut window showing internal anatomy)

Brachiopods are sessile, benthic, filter-feeding, marine invertebrates. They first appear in Cambrian rocks and were abundant in Earth's oceans throughout the Paleozoic. They were also common in Mesozoic oceans, but are scarce in modern oceanic biotas. Brachiopods have two shells, called valves, that are usually calcareous (made of calcite - CaCO3 - calcium carbonate). Each shell of a brachiopod is bilaterally symmetrical, unlike each shell of a bivalve (clam).

This fossil brachiopod's shell is now composed of pyrite ("fool's gold" - FeS2, iron sulfide), a preservation style referred to as replacement. The specimen comes from the Middle Devonian Silica Formation (also known as the Silica Shale) in northwestern Ohio. Pyritized fossils are relatively common in the unit - pyrite can replace shells or it can be a coarsely-crystalline coating atop the calcareous shells. Remarkably, this brachiopod's spiral brachidium is visible through the window cut into the shell - the brachidium has been completely pyrizited. In spiriferid brachiopods, the brachidium is an internal, calcified support structure for the lophophore, which is the brachiopod's filter feeding apparatus.

The most common fossil replacement minerals are quartz, pyrite, and apatite. Quartz is SiO2 (silica) - fossils that have been quartz-replaced are said to be silicified (silicification). Many silicified fossils have rounded to pustulose structures covering their surfaces. These are called beekite rings, but they're composed of ordinary quartz. Replacement by apatite (calcium phosphate) is called phosphatization.

Other minerals have also been found replacing minerals - many are quite rare. Reported fossil replacement minerals include: anglesite, apatite, barite, calamine, calcite, cassiterite, celestite, cerargyrite, cerussite, chalcocite, cinnabar, copper, dolomite, fluorite, galena, garnet, glauconite, gumbelite, gypsum, hematite, kaolinite, limonite, magnesite, malachite, marcasite, margarite, opal, pyrite, romanechite/psilomelane, siderite, silica/quartz, silver, smithsonite, specular hematite, sphalerite, sulfur, uranium minerals, and vivianite.
(List mostly from info. in Hartzell, 1906 and Klein & Hurlbut, 1985)

Classification: Animalia, Brachiopoda, Articulata (a.k.a. Rhynchonelliformea), Spiriferida, Hysterolitidae

Stratigraphy: Silica Formation, Givetian Stage, upper Middle Devonian

Locality: unrecorded / undisclosed, but likely from a quarry in northwestern Ohio, USA

Paraspirifer bownockeri Stewart, 1927 - pyritized fossil brachiopod from the Devonian of Ohio, USA (view of ventral valve, with a cut window showing internal anatomy)

Brachiopods are sessile, benthic, filter-feeding, marine invertebrates. They first appear in Cambrian rocks and were abundant in Earth's oceans throughout the Paleozoic. They were also common in Mesozoic oceans, but are scarce in modern oceanic biotas. Brachiopods have two shells, called valves, that are usually calcareous (made of calcite - CaCO3 - calcium carbonate). Each shell of a brachiopod is bilaterally symmetrical, unlike each shell of a bivalve (clam).

This fossil brachiopod's shell is now composed of pyrite ("fool's gold" - FeS2, iron sulfide), a preservation style referred to as replacement. The specimen comes from the Middle Devonian Silica Formation (also known as the Silica Shale) in northwestern Ohio. Pyritized fossils are relatively common in the unit - pyrite can replace shells or it can be a coarsely-crystalline coating atop the calcareous shells. Remarkably, this brachiopod's spiral brachidium is visible through the window cut into the shell - the brachidium has been completely pyrizited. In spiriferid brachiopods, the brachidium is an internal, calcified support structure for the lophophore, which is the brachiopod's filter feeding apparatus.

The most common fossil replacement minerals are quartz, pyrite, and apatite. Quartz is SiO2 (silica) - fossils that have been quartz-replaced are said to be silicified (silicification). Many silicified fossils have rounded to pustulose structures covering their surfaces. These are called beekite rings, but they're composed of ordinary quartz. Replacement by apatite (calcium phosphate) is called phosphatization.

Other minerals have also been found replacing minerals - many are quite rare. Reported fossil replacement minerals include: anglesite, apatite, barite, calamine, calcite, cassiterite, celestite, cerargyrite, cerussite, chalcocite, cinnabar, copper, dolomite, fluorite, galena, garnet, glauconite, gumbelite, gypsum, hematite, kaolinite, limonite, magnesite, malachite, marcasite, margarite, opal, pyrite, romanechite/psilomelane, siderite, silica/quartz, silver, smithsonite, specular hematite, sphalerite, sulfur, uranium minerals, and vivianite.
(List mostly from info. in Hartzell, 1906 and Klein & Hurlbut, 1985)

Classification: Animalia, Brachiopoda, Articulata (a.k.a. Rhynchonelliformea), Spiriferida, Hysterolitidae

Stratigraphy: Silica Formation, Givetian Stage, upper Middle Devonian

Locality: unrecorded / undisclosed, but likely from a quarry in northwestern Ohio, USA

Pyritized Paraspirifer bownockeri fossil brachiopod with encrusting auloporid corals from the Devonian of Ohio, USA.

Auloporids are a group of extinct tabulate corals. They consist of calcareous colonies of hard substrate-encrusting, trumpet-shaped corallites. They first appear in the Ordovician and go extinct in the Permian. The auloporids seen here are encrusting a spiriferid brachiopod from Ohio's famous Silica Formation, a richly fossiliferous unit.

Classification of corals: Animalia, Cnidaria, Anthozoa, Tabulata, Auloporidae

Classification of brachiopod: Animalia, Brachiopoda, Articulata (a.k.a. Rhynchonelliformea), Spiriferida, Hysterolitidae

Stratigraphy: Silica Formation, Givetian Stage, upper Middle Devonian

Locality: quarry in the Sylvania area, far-northern Lucas County, northwestern Ohio, USA

Pyritized Paraspirifer bownockeri fossil brachiopod with encrusting auloporid corals from the Devonian of Ohio, USA.

Auloporids are a group of extinct tabulate corals. They consist of calcareous colonies of hard substrate-encrusting, trumpet-shaped corallites. They first appear in the Ordovician and go extinct in the Permian. The auloporids seen here are encrusting a spiriferid brachiopod from Ohio's famous Silica Formation, a richly fossiliferous unit.

Classification of corals: Animalia, Cnidaria, Anthozoa, Tabulata, Auloporidae

Classification of brachiopod: Animalia, Brachiopoda, Articulata (a.k.a. Rhynchonelliformea), Spiriferida, Hysterolitidae

Stratigraphy: Silica Formation, Givetian Stage, upper Middle Devonian

Locality: quarry in the Sylvania area, far-northern Lucas County, northwestern Ohio, USA

Pyritized Paraspirifer bownockeri fossil brachiopod with encrusting auloporid corals from the Devonian of Ohio, USA.

Auloporids are a group of extinct tabulate corals. They consist of calcareous colonies of hard substrate-encrusting, trumpet-shaped corallites. They first appear in the Ordovician and go extinct in the Permian. The auloporids seen here are encrusting a spiriferid brachiopod from Ohio's famous Silica Formation, a richly fossiliferous unit.

Classification of corals: Animalia, Cnidaria, Anthozoa, Tabulata, Auloporidae

Classification of brachiopod: Animalia, Brachiopoda, Articulata (a.k.a. Rhynchonelliformea), Spiriferida, Hysterolitidae

Stratigraphy: Silica Formation, Givetian Stage, upper Middle Devonian

Locality: quarry in the Sylvania area, far-northern Lucas County, northwestern Ohio, USA

Pyritized Paraspirifer bownockeri fossil brachiopod with encrusting auloporid corals from the Devonian of Ohio, USA.

Auloporids are a group of extinct tabulate corals. They consist of calcareous colonies of hard substrate-encrusting, trumpet-shaped corallites. They first appear in the Ordovician and go extinct in the Permian. The auloporids seen here are encrusting a spiriferid brachiopod from Ohio's famous Silica Formation, a richly fossiliferous unit.

Classification of corals: Animalia, Cnidaria, Anthozoa, Tabulata, Auloporidae

Classification of brachiopod: Animalia, Brachiopoda, Articulata (a.k.a. Rhynchonelliformea), Spiriferida, Hysterolitidae

Stratigraphy: Silica Formation, Givetian Stage, upper Middle Devonian

Locality: quarry in the Sylvania area, far-northern Lucas County, northwestern Ohio, USA

Pyritized Paraspirifer bownockeri fossil brachiopod with encrusting auloporid corals from the Devonian of Ohio, USA.

Auloporids are a group of extinct tabulate corals. They consist of calcareous colonies of hard substrate-encrusting, trumpet-shaped corallites. They first appear in the Ordovician and go extinct in the Permian. The auloporids seen here are encrusting a spiriferid brachiopod from Ohio's famous Silica Formation, a richly fossiliferous unit.

Classification of corals: Animalia, Cnidaria, Anthozoa, Tabulata, Auloporidae

Classification of brachiopod: Animalia, Brachiopoda, Articulata (a.k.a. Rhynchonelliformea), Spiriferida, Hysterolitidae

Stratigraphy: Silica Formation, Givetian Stage, upper Middle Devonian

Locality: quarry in the Sylvania area, far-northern Lucas County, northwestern Ohio, USA

Paraspirifer bownockeri Stewart, 1927 - pyritized fossil brachiopod from the Devonian of Ohio, USA (posterior view; ~5.6 centimeters across at its widest)

Brachiopods are sessile, benthic, filter-feeding, marine invertebrates. They first appear in Cambrian rocks and were abundant in Earth's oceans throughout the Paleozoic. They were also common in Mesozoic oceans, but are scarce in modern oceanic biotas. Brachiopods have two shells, called valves, that are usually calcareous (made of calcite - CaCO3 - calcium carbonate). Each shell of a brachiopod is bilaterally symmetrical, unlike each shell of a bivalve (clam).

This fossil brachiopod's shell is now composed of pyrite ("fool's gold" - FeS2, iron sulfide), a preservation style referred to as replacement. The specimen comes from the Middle Devonian Silica Formation (also known as the Silica Shale) in northwestern Ohio. Pyritized fossils are relatively common in the unit - pyrite can replace shells or it can be a coarsely-crystalline coating atop the calcareous shells.

The most common fossil replacement minerals are quartz, pyrite, and apatite. Quartz is SiO2 (silica) - fossils that have been quartz-replaced are said to be silicified (silicification). Many silicified fossils have rounded to pustulose structures covering their surfaces. These are called beekite rings, but they're composed of ordinary quartz. Replacement by apatite (calcium phosphate) is called phosphatization.

Other minerals have also been found replacing minerals - many are quite rare. Reported fossil replacement minerals include: anglesite, apatite, barite, calamine, calcite, cassiterite, celestite, cerargyrite, cerussite, chalcocite, cinnabar, copper, dolomite, fluorite, galena, garnet, glauconite, gumbelite, gypsum, hematite, kaolinite, limonite, magnesite, malachite, marcasite, margarite, opal, pyrite, romanechite/psilomelane, siderite, silica/quartz, silver, smithsonite, specular hematite, sphalerite, sulfur, uranium minerals, and vivianite.
(List mostly from info. in Hartzell, 1906 and Klein & Hurlbut, 1985)

Classification: Animalia, Brachiopoda, Articulata (a.k.a. Rhynchonelliformea), Spiriferida, Hysterolitidae

Stratigraphy: Silica Formation, Givetian Stage, upper Middle Devonian

Locality: quarry in the Sylvania area, far-northern Lucas County, northwestern Ohio, USA

Paraspirifer bownockeri Stewart, 1927 - pyritized fossil brachiopod from the Devonian of Ohio, USA (anterior view; ~4.3 centimeters across at its widest)

Brachiopods are sessile, benthic, filter-feeding, marine invertebrates. They first appear in Cambrian rocks and were abundant in Earth's oceans throughout the Paleozoic. They were also common in Mesozoic oceans, but are scarce in modern oceanic biotas. Brachiopods have two shells, called valves, that are usually calcareous (made of calcite - CaCO3 - calcium carbonate). Each shell of a brachiopod is bilaterally symmetrical, unlike each shell of a bivalve (clam).

This fossil brachiopod's shell is now composed of pyrite ("fool's gold" - FeS2, iron sulfide), a preservation style referred to as replacement. The specimen comes from the Middle Devonian Silica Formation (also known as the Silica Shale) in northwestern Ohio. Pyritized fossils are relatively common in the unit - pyrite can replace shells or it can be a coarsely-crystalline coating atop the calcareous shells.

The most common fossil replacement minerals are quartz, pyrite, and apatite. Quartz is SiO2 (silica) - fossils that have been quartz-replaced are said to be silicified (silicification). Many silicified fossils have rounded to pustulose structures covering their surfaces. These are called beekite rings, but they're composed of ordinary quartz. Replacement by apatite (calcium phosphate) is called phosphatization.

Other minerals have also been found replacing minerals - many are quite rare. Reported fossil replacement minerals include: anglesite, apatite, barite, calamine, calcite, cassiterite, celestite, cerargyrite, cerussite, chalcocite, cinnabar, copper, dolomite, fluorite, galena, garnet, glauconite, gumbelite, gypsum, hematite, kaolinite, limonite, magnesite, malachite, marcasite, margarite, opal, pyrite, romanechite/psilomelane, siderite, silica/quartz, silver, smithsonite, specular hematite, sphalerite, sulfur, uranium minerals, and vivianite.
(List mostly from info. in Hartzell, 1906 and Klein & Hurlbut, 1985)

Classification: Animalia, Brachiopoda, Articulata (a.k.a. Rhynchonelliformea), Spiriferida, Hysterolitidae

Stratigraphy: Silica Formation, Givetian Stage, upper Middle Devonian

Locality: quarry in the Sylvania area, far-northern Lucas County, northwestern Ohio, USA

Paraspirifer bownockeri Stewart, 1927 - pyritized fossil brachiopod from the Devonian of Ohio, USA (posterior view; ~5.6 centimeters across at its widest)

Brachiopods are sessile, benthic, filter-feeding, marine invertebrates. They first appear in Cambrian rocks and were abundant in Earth's oceans throughout the Paleozoic. They were also common in Mesozoic oceans, but are scarce in modern oceanic biotas. Brachiopods have two shells, called valves, that are usually calcareous (made of calcite - CaCO3 - calcium carbonate). Each shell of a brachiopod is bilaterally symmetrical, unlike each shell of a bivalve (clam).

This fossil brachiopod's shell is now composed of pyrite ("fool's gold" - FeS2, iron sulfide), a preservation style referred to as replacement. The specimen comes from the Middle Devonian Silica Formation (also known as the Silica Shale) in northwestern Ohio. Pyritized fossils are relatively common in the unit - pyrite can replace shells or it can be a coarsely-crystalline coating atop the calcareous shells.

The most common fossil replacement minerals are quartz, pyrite, and apatite. Quartz is SiO2 (silica) - fossils that have been quartz-replaced are said to be silicified (silicification). Many silicified fossils have rounded to pustulose structures covering their surfaces. These are called beekite rings, but they're composed of ordinary quartz. Replacement by apatite (calcium phosphate) is called phosphatization.

Other minerals have also been found replacing minerals - many are quite rare. Reported fossil replacement minerals include: anglesite, apatite, barite, calamine, calcite, cassiterite, celestite, cerargyrite, cerussite, chalcocite, cinnabar, copper, dolomite, fluorite, galena, garnet, glauconite, gumbelite, gypsum, hematite, kaolinite, limonite, magnesite, malachite, marcasite, margarite, opal, pyrite, romanechite/psilomelane, siderite, silica/quartz, silver, smithsonite, specular hematite, sphalerite, sulfur, uranium minerals, and vivianite.
(List mostly from info. in Hartzell, 1906 and Klein & Hurlbut, 1985)

Classification: Animalia, Brachiopoda, Articulata (a.k.a. Rhynchonelliformea), Spiriferida, Hysterolitidae

Stratigraphy: Silica Formation, Givetian Stage, upper Middle Devonian

Locality: quarry in the Sylvania area, far-northern Lucas County, northwestern Ohio, USA

Paraspirifer bownockeri Stewart, 1927 - pyritized fossil brachiopod from the Devonian of Ohio, USA (view of dorsal valve; ~4.45 centimeters across at its widest)

Brachiopods are sessile, benthic, filter-feeding, marine invertebrates. They first appear in Cambrian rocks and were abundant in Earth's oceans throughout the Paleozoic. They were also common in Mesozoic oceans, but are scarce in modern oceanic biotas. Brachiopods have two shells, called valves, that are usually calcareous (made of calcite - CaCO3 - calcium carbonate). Each shell of a brachiopod is bilaterally symmetrical, unlike each shell of a bivalve (clam).

This fossil brachiopod's shell is now composed of pyrite ("fool's gold" - FeS2, iron sulfide), a preservation style referred to as replacement. The specimen comes from the Middle Devonian Silica Formation (also known as the Silica Shale) in northwestern Ohio. Pyritized fossils are relatively common in the unit - pyrite can replace shells or it can be a coarsely-crystalline coating atop the calcareous shells.

The most common fossil replacement minerals are quartz, pyrite, and apatite. Quartz is SiO2 (silica) - fossils that have been quartz-replaced are said to be silicified (silicification). Many silicified fossils have rounded to pustulose structures covering their surfaces. These are called beekite rings, but they're composed of ordinary quartz. Replacement by apatite (calcium phosphate) is called phosphatization.

Other minerals have also been found replacing minerals - many are quite rare. Reported fossil replacement minerals include: anglesite, apatite, barite, calamine, calcite, cassiterite, celestite, cerargyrite, cerussite, chalcocite, cinnabar, copper, dolomite, fluorite, galena, garnet, glauconite, gumbelite, gypsum, hematite, kaolinite, limonite, magnesite, malachite, marcasite, margarite, opal, pyrite, romanechite/psilomelane, siderite, silica/quartz, silver, smithsonite, specular hematite, sphalerite, sulfur, uranium minerals, and vivianite.
(List mostly from info. in Hartzell, 1906 and Klein & Hurlbut, 1985)

Classification: Animalia, Brachiopoda, Articulata (a.k.a. Rhynchonelliformea), Spiriferida, Hysterolitidae

Stratigraphy: Silica Formation, Givetian Stage, upper Middle Devonian

Locality: quarry in the Sylvania area, far-northern Lucas County, northwestern Ohio, USA

Paraspirifer bownockeri Stewart, 1927 - pyritized fossil brachiopod from the Devonian of Ohio, USA (view of dorsal valve; ~4.3 centimeters across at its widest)

Brachiopods are sessile, benthic, filter-feeding, marine invertebrates. They first appear in Cambrian rocks and were abundant in Earth's oceans throughout the Paleozoic. They were also common in Mesozoic oceans, but are scarce in modern oceanic biotas. Brachiopods have two shells, called valves, that are usually calcareous (made of calcite - CaCO3 - calcium carbonate). Each shell of a brachiopod is bilaterally symmetrical, unlike each shell of a bivalve (clam).

This fossil brachiopod's shell is now composed of pyrite ("fool's gold" - FeS2, iron sulfide), a preservation style referred to as replacement. The specimen comes from the Middle Devonian Silica Formation (also known as the Silica Shale) in northwestern Ohio. Pyritized fossils are relatively common in the unit - pyrite can replace shells or it can be a coarsely-crystalline coating atop the calcareous shells.

The most common fossil replacement minerals are quartz, pyrite, and apatite. Quartz is SiO2 (silica) - fossils that have been quartz-replaced are said to be silicified (silicification). Many silicified fossils have rounded to pustulose structures covering their surfaces. These are called beekite rings, but they're composed of ordinary quartz. Replacement by apatite (calcium phosphate) is called phosphatization.

Other minerals have also been found replacing minerals - many are quite rare. Reported fossil replacement minerals include: anglesite, apatite, barite, calamine, calcite, cassiterite, celestite, cerargyrite, cerussite, chalcocite, cinnabar, copper, dolomite, fluorite, galena, garnet, glauconite, gumbelite, gypsum, hematite, kaolinite, limonite, magnesite, malachite, marcasite, margarite, opal, pyrite, romanechite/psilomelane, siderite, silica/quartz, silver, smithsonite, specular hematite, sphalerite, sulfur, uranium minerals, and vivianite.
(List mostly from info. in Hartzell, 1906 and Klein & Hurlbut, 1985)

Classification: Animalia, Brachiopoda, Articulata (a.k.a. Rhynchonelliformea), Spiriferida, Hysterolitidae

Stratigraphy: Silica Formation, Givetian Stage, upper Middle Devonian

Locality: quarry in the Sylvania area, far-northern Lucas County, northwestern Ohio, USA

Paraspirifer bownockeri Stewart, 1927 - pyritized fossil brachiopod from the Devonian of Ohio, USA (anterodorsal view; ~4.3 centimeters across at its widest)

Brachiopods are sessile, benthic, filter-feeding, marine invertebrates. They first appear in Cambrian rocks and were abundant in Earth's oceans throughout the Paleozoic. They were also common in Mesozoic oceans, but are scarce in modern oceanic biotas. Brachiopods have two shells, called valves, that are usually calcareous (made of calcite - CaCO3 - calcium carbonate). Each shell of a brachiopod is bilaterally symmetrical, unlike each shell of a bivalve (clam).

This fossil brachiopod's shell is now composed of pyrite ("fool's gold" - FeS2, iron sulfide), a preservation style referred to as replacement. The specimen comes from the Middle Devonian Silica Formation (also known as the Silica Shale) in northwestern Ohio. Pyritized fossils are relatively common in the unit - pyrite can replace shells or it can be a coarsely-crystalline coating atop the calcareous shells.

The most common fossil replacement minerals are quartz, pyrite, and apatite. Quartz is SiO2 (silica) - fossils that have been quartz-replaced are said to be silicified (silicification). Many silicified fossils have rounded to pustulose structures covering their surfaces. These are called beekite rings, but they're composed of ordinary quartz. Replacement by apatite (calcium phosphate) is called phosphatization.

Other minerals have also been found replacing minerals - many are quite rare. Reported fossil replacement minerals include: anglesite, apatite, barite, calamine, calcite, cassiterite, celestite, cerargyrite, cerussite, chalcocite, cinnabar, copper, dolomite, fluorite, galena, garnet, glauconite, gumbelite, gypsum, hematite, kaolinite, limonite, magnesite, malachite, marcasite, margarite, opal, pyrite, romanechite/psilomelane, siderite, silica/quartz, silver, smithsonite, specular hematite, sphalerite, sulfur, uranium minerals, and vivianite.
(List mostly from info. in Hartzell, 1906 and Klein & Hurlbut, 1985)

Classification: Animalia, Brachiopoda, Articulata (a.k.a. Rhynchonelliformea), Spiriferida, Hysterolitidae

Stratigraphy: Silica Formation, Givetian Stage, upper Middle Devonian

Locality: quarry in the Sylvania area, far-northern Lucas County, northwestern Ohio, USA

Paraspirifer bownockeri Stewart, 1927 - pyritized fossil brachiopod from the Devonian of Ohio, USA (posterior view; ~4.3 centimeters across at its widest)

Brachiopods are sessile, benthic, filter-feeding, marine invertebrates. They first appear in Cambrian rocks and were abundant in Earth's oceans throughout the Paleozoic. They were also common in Mesozoic oceans, but are scarce in modern oceanic biotas. Brachiopods have two shells, called valves, that are usually calcareous (made of calcite - CaCO3 - calcium carbonate). Each shell of a brachiopod is bilaterally symmetrical, unlike each shell of a bivalve (clam).

This fossil brachiopod's shell is now composed of pyrite ("fool's gold" - FeS2, iron sulfide), a preservation style referred to as replacement. The specimen comes from the Middle Devonian Silica Formation (also known as the Silica Shale) in northwestern Ohio. Pyritized fossils are relatively common in the unit - pyrite can replace shells or it can be a coarsely-crystalline coating atop the calcareous shells.

The most common fossil replacement minerals are quartz, pyrite, and apatite. Quartz is SiO2 (silica) - fossils that have been quartz-replaced are said to be silicified (silicification). Many silicified fossils have rounded to pustulose structures covering their surfaces. These are called beekite rings, but they're composed of ordinary quartz. Replacement by apatite (calcium phosphate) is called phosphatization.

Other minerals have also been found replacing minerals - many are quite rare. Reported fossil replacement minerals include: anglesite, apatite, barite, calamine, calcite, cassiterite, celestite, cerargyrite, cerussite, chalcocite, cinnabar, copper, dolomite, fluorite, galena, garnet, glauconite, gumbelite, gypsum, hematite, kaolinite, limonite, magnesite, malachite, marcasite, margarite, opal, pyrite, romanechite/psilomelane, siderite, silica/quartz, silver, smithsonite, specular hematite, sphalerite, sulfur, uranium minerals, and vivianite.
(List mostly from info. in Hartzell, 1906 and Klein & Hurlbut, 1985)

Classification: Animalia, Brachiopoda, Articulata (a.k.a. Rhynchonelliformea), Spiriferida, Hysterolitidae

Stratigraphy: Silica Formation, Givetian Stage, upper Middle Devonian

Locality: quarry in the Sylvania area, far-northern Lucas County, northwestern Ohio, USA

Paraspirifer bownockeri Stewart, 1927 - pyritized fossil brachiopod from the Devonian of Ohio, USA (view of dorsal valve; ~5.6 centimeters across at its widest)

Brachiopods are sessile, benthic, filter-feeding, marine invertebrates. They first appear in Cambrian rocks and were abundant in Earth's oceans throughout the Paleozoic. They were also common in Mesozoic oceans, but are scarce in modern oceanic biotas. Brachiopods have two shells, called valves, that are usually calcareous (made of calcite - CaCO3 - calcium carbonate). Each shell of a brachiopod is bilaterally symmetrical, unlike each shell of a bivalve (clam).

This fossil brachiopod's shell is now composed of pyrite ("fool's gold" - FeS2, iron sulfide), a preservation style referred to as replacement. The specimen comes from the Middle Devonian Silica Formation (also known as the Silica Shale) in northwestern Ohio. Pyritized fossils are relatively common in the unit - pyrite can replace shells or it can be a coarsely-crystalline coating atop the calcareous shells.

The most common fossil replacement minerals are quartz, pyrite, and apatite. Quartz is SiO2 (silica) - fossils that have been quartz-replaced are said to be silicified (silicification). Many silicified fossils have rounded to pustulose structures covering their surfaces. These are called beekite rings, but they're composed of ordinary quartz. Replacement by apatite (calcium phosphate) is called phosphatization.

Other minerals have also been found replacing minerals - many are quite rare. Reported fossil replacement minerals include: anglesite, apatite, barite, calamine, calcite, cassiterite, celestite, cerargyrite, cerussite, chalcocite, cinnabar, copper, dolomite, fluorite, galena, garnet, glauconite, gumbelite, gypsum, hematite, kaolinite, limonite, magnesite, malachite, marcasite, margarite, opal, pyrite, romanechite/psilomelane, siderite, silica/quartz, silver, smithsonite, specular hematite, sphalerite, sulfur, uranium minerals, and vivianite.
(List mostly from info. in Hartzell, 1906 and Klein & Hurlbut, 1985)

Classification: Animalia, Brachiopoda, Articulata (a.k.a. Rhynchonelliformea), Spiriferida, Hysterolitidae

Stratigraphy: Silica Formation, Givetian Stage, upper Middle Devonian

Locality: quarry in the Sylvania area, far-northern Lucas County, northwestern Ohio, USA

Paraspirifer bownockeri Stewart, 1927 - pyritized fossil brachiopod from the Devonian of Ohio, USA (view of ventral valve; ~4.45 centimeters across at its widest)

Brachiopods are sessile, benthic, filter-feeding, marine invertebrates. They first appear in Cambrian rocks and were abundant in Earth's oceans throughout the Paleozoic. They were also common in Mesozoic oceans, but are scarce in modern oceanic biotas. Brachiopods have two shells, called valves, that are usually calcareous (made of calcite - CaCO3 - calcium carbonate). Each shell of a brachiopod is bilaterally symmetrical, unlike each shell of a bivalve (clam).

This fossil brachiopod's shell is now composed of pyrite ("fool's gold" - FeS2, iron sulfide), a preservation style referred to as replacement. The specimen comes from the Middle Devonian Silica Formation (also known as the Silica Shale) in northwestern Ohio. Pyritized fossils are relatively common in the unit - pyrite can replace shells or it can be a coarsely-crystalline coating atop the calcareous shells.

The most common fossil replacement minerals are quartz, pyrite, and apatite. Quartz is SiO2 (silica) - fossils that have been quartz-replaced are said to be silicified (silicification). Many silicified fossils have rounded to pustulose structures covering their surfaces. These are called beekite rings, but they're composed of ordinary quartz. Replacement by apatite (calcium phosphate) is called phosphatization.

Other minerals have also been found replacing minerals - many are quite rare. Reported fossil replacement minerals include: anglesite, apatite, barite, calamine, calcite, cassiterite, celestite, cerargyrite, cerussite, chalcocite, cinnabar, copper, dolomite, fluorite, galena, garnet, glauconite, gumbelite, gypsum, hematite, kaolinite, limonite, magnesite, malachite, marcasite, margarite, opal, pyrite, romanechite/psilomelane, siderite, silica/quartz, silver, smithsonite, specular hematite, sphalerite, sulfur, uranium minerals, and vivianite.
(List mostly from info. in Hartzell, 1906 and Klein & Hurlbut, 1985)

Classification: Animalia, Brachiopoda, Articulata (a.k.a. Rhynchonelliformea), Spiriferida, Hysterolitidae

Stratigraphy: Silica Formation, Givetian Stage, upper Middle Devonian

Locality: quarry in the Sylvania area, far-northern Lucas County, northwestern Ohio, USA

Paraspirifer bownockeri Stewart, 1927 - pyritized fossil brachiopod from the Devonian of Ohio, USA (anterodorsal view; ~5.6 centimeters across at its widest)

Brachiopods are sessile, benthic, filter-feeding, marine invertebrates. They first appear in Cambrian rocks and were abundant in Earth's oceans throughout the Paleozoic. They were also common in Mesozoic oceans, but are scarce in modern oceanic biotas. Brachiopods have two shells, called valves, that are usually calcareous (made of calcite - CaCO3 - calcium carbonate). Each shell of a brachiopod is bilaterally symmetrical, unlike each shell of a bivalve (clam).

This fossil brachiopod's shell is now composed of pyrite ("fool's gold" - FeS2, iron sulfide), a preservation style referred to as replacement. The specimen comes from the Middle Devonian Silica Formation (also known as the Silica Shale) in northwestern Ohio. Pyritized fossils are relatively common in the unit - pyrite can replace shells or it can be a coarsely-crystalline coating atop the calcareous shells.

The most common fossil replacement minerals are quartz, pyrite, and apatite. Quartz is SiO2 (silica) - fossils that have been quartz-replaced are said to be silicified (silicification). Many silicified fossils have rounded to pustulose structures covering their surfaces. These are called beekite rings, but they're composed of ordinary quartz. Replacement by apatite (calcium phosphate) is called phosphatization.

Other minerals have also been found replacing minerals - many are quite rare. Reported fossil replacement minerals include: anglesite, apatite, barite, calamine, calcite, cassiterite, celestite, cerargyrite, cerussite, chalcocite, cinnabar, copper, dolomite, fluorite, galena, garnet, glauconite, gumbelite, gypsum, hematite, kaolinite, limonite, magnesite, malachite, marcasite, margarite, opal, pyrite, romanechite/psilomelane, siderite, silica/quartz, silver, smithsonite, specular hematite, sphalerite, sulfur, uranium minerals, and vivianite.
(List mostly from info. in Hartzell, 1906 and Klein & Hurlbut, 1985)

Classification: Animalia, Brachiopoda, Articulata (a.k.a. Rhynchonelliformea), Spiriferida, Hysterolitidae

Stratigraphy: Silica Formation, Givetian Stage, upper Middle Devonian

Locality: quarry in the Sylvania area, far-northern Lucas County, northwestern Ohio, USA