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Blue Dinosaur Royal Ontario Museum
Taxa Argentinosauria

Blue Dinosaur Royal Ontario Museum

museum United States Argentinosauria Argentinosauridae +3
Museum of Zoology of the University of São Paulo, Brazil
Taxa Tapuiasaurus

Museum of Zoology of the University of São Paulo, Brazil

museum Brazil Tapuiasaurus
Fossil of Mosasaurus, an extinct mosasaur, reconstruction of the Mosasaurus of Bemelen. Took the photo at Natural History Museum of Maastricht

Fossil of Mosasaurus, an extinct mosasaur, reconstruction of the Mosasaurus of Bemelen. Took the photo at Natural History Museum of Maastricht

museum fossil Moanasaurus Mosasaurus
Henan Geological Museum, Zhengzhou, China. Complete indexed photo collection at WorldHistoryPics.com.
Taxa Placoolithus

Henan Geological Museum, Zhengzhou, China. Complete indexed photo collection at WorldHistoryPics.com.

museum China Placoolithus
Herbivorous dinosaur found in the Al-khoudh area.  This dinosaur is similar to the Zalmoxes and Rhabdodon dinosaurs.  The skeleton in the Bait Al Baranda Museum was assembled from bones borrowed from several museums.

Herbivorous dinosaur found in the Al-khoudh area. This dinosaur is similar to the Zalmoxes and Rhabdodon dinosaurs. The skeleton in the Bait Al Baranda Museum was assembled from bones borrowed from several museums.

bone museum Dinosauria Mochlodon +3
Banded fine-grained pyrite in shale from the Precambrian of Australia. (public display, Leadville Mining Museum, Leadville, Colorado, USA)
A mineral is a naturally-occurring, solid, inorganic, crystalline substance having a fairly definite chemical composition and having fairly definite physical properties.  At its simplest, a mineral is a naturally-occurring solid chemical.  Currently, there are over 4900 named and described minerals - about 200 of them are common and about 20 of them are very common.  Mineral classification is based on anion chemistry.  Major categories of minerals are: elements, sulfides, oxides, halides, carbonates, sulfates, phosphates, and silicates.
The sulfide minerals contain one or more sulfide anions (S-2).  The sulfides are usually considered together with the arsenide minerals, the sulfarsenide minerals, and the telluride minerals.  Many sulfides are economically significant, as they occur commonly in ores.  The metals that combine with S-2 are mainly Fe, Cu, Ni, Ag, etc.  Most sulfides have a metallic luster, are moderately soft, and are noticeably heavy for their size.  These minerals will not form in the presence of free oxygen.  Under an oxygen-rich atmosphere, sulfide minerals tend to chemically weather to various oxide and hydroxide minerals.
Pyrite is a common iron sulfide mineral (FeS2).  It’s nickname is “fool's gold”.  Pyrite has a metallic luster, brassy gold color (in contrast to the deep rich yellow gold color of true gold - www.flickr.com/photos/jsjgeology/sets/72157651325153769/), dark gray to black streak, is hard (H=6 to 6.5), has no cleavage, and is moderately heavy for its size.  It often forms cubic crystals or pyritohedrons (crystals having pentagonal faces).
Pyrite is common in many hydrothermal veins, shales, coals, various metamorphic rocks, and massive sulfide deposits.
The rock shown above consists of numerous bands of fine-grained pyrite interbedded with dark shale.  Published research has shown that the pyrite is diagenetic, formed by sulfate reduction from sulfate-bearing groundwater that moved along bedding planes of the Urquhart Shale host rocks (see Painter et al., 1999).  The sulfate source was evaporitic gypsum-anhydrite-barite in the same stratigraphic unit.
Stratigraphy: Urquhart Shale, Mount Isa Group, Mesoproterozoic, ~1655 Ma
Age of metamorphism: peak greenschist-facies metamorphism at ~1505 Ma during the Isan Orogeny
Locality: Mount Isa Mines, northwestern Queensland, northeastern Australia


Some info. from:
Kawasaki & Symons (2010) - Dating of Mesoproterozoic metamorphism in the Mount Isa and George Fisher Zn-Pb-Cu-Ag deposits, Australia, by paleomagnetism.  American Geophysical Union, Fall Meeting 2010, Abstract GP33C-0953.
Painter et al. (1999) - Sedimentologic, petrographic, and sulfur isotope constraints on fine-grained pyrite formation at Mount Isa Mine and environs, northwest Queensland, Australia.  Economic Geology 94: 883-912.


Photo gallery of pyrite:

www.mindat.org/gallery.php?min=3314
Intervals Mesoproterozoic

Banded fine-grained pyrite in shale from the Precambrian of Australia. (public display, Leadville Mining Museum, Leadville, Colorado, USA) A mineral is a naturally-occurring, solid, inorganic, crystalline substance having a fairly definite chemical composition and having fairly definite physical properties. At its simplest, a mineral is a naturally-occurring solid chemical. Currently, there are over 4900 named and described minerals - about 200 of them are common and about 20 of them are very common. Mineral classification is based on anion chemistry. Major categories of minerals are: elements, sulfides, oxides, halides, carbonates, sulfates, phosphates, and silicates. The sulfide minerals contain one or more sulfide anions (S-2). The sulfides are usually considered together with the arsenide minerals, the sulfarsenide minerals, and the telluride minerals. Many sulfides are economically significant, as they occur commonly in ores. The metals that combine with S-2 are mainly Fe, Cu, Ni, Ag, etc. Most sulfides have a metallic luster, are moderately soft, and are noticeably heavy for their size. These minerals will not form in the presence of free oxygen. Under an oxygen-rich atmosphere, sulfide minerals tend to chemically weather to various oxide and hydroxide minerals. Pyrite is a common iron sulfide mineral (FeS2). It’s nickname is “fool's gold”. Pyrite has a metallic luster, brassy gold color (in contrast to the deep rich yellow gold color of true gold - www.flickr.com/photos/jsjgeology/sets/72157651325153769/), dark gray to black streak, is hard (H=6 to 6.5), has no cleavage, and is moderately heavy for its size. It often forms cubic crystals or pyritohedrons (crystals having pentagonal faces). Pyrite is common in many hydrothermal veins, shales, coals, various metamorphic rocks, and massive sulfide deposits. The rock shown above consists of numerous bands of fine-grained pyrite interbedded with dark shale. Published research has shown that the pyrite is diagenetic, formed by sulfate reduction from sulfate-bearing groundwater that moved along bedding planes of the Urquhart Shale host rocks (see Painter et al., 1999). The sulfate source was evaporitic gypsum-anhydrite-barite in the same stratigraphic unit. Stratigraphy: Urquhart Shale, Mount Isa Group, Mesoproterozoic, ~1655 Ma Age of metamorphism: peak greenschist-facies metamorphism at ~1505 Ma during the Isan Orogeny Locality: Mount Isa Mines, northwestern Queensland, northeastern Australia Some info. from: Kawasaki & Symons (2010) - Dating of Mesoproterozoic metamorphism in the Mount Isa and George Fisher Zn-Pb-Cu-Ag deposits, Australia, by paleomagnetism. American Geophysical Union, Fall Meeting 2010, Abstract GP33C-0953. Painter et al. (1999) - Sedimentologic, petrographic, and sulfur isotope constraints on fine-grained pyrite formation at Mount Isa Mine and environs, northwest Queensland, Australia. Economic Geology 94: 883-912. Photo gallery of pyrite: www.mindat.org/gallery.php?min=3314

museum Australia United States
This image shows a 2.1 billion year old rock containing black-banded ironstone. The rock weighs about 8.5 tons, and is approximately two meters high, three meters wide, and one meter thick. It was found in North America and belongs to the National Museum of Mineralogy and Geology, Dresden, Germany. The rock is located at +51°2'34.84" +13°45'26.67".
Intervals Rhyacian

This image shows a 2.1 billion year old rock containing black-banded ironstone. The rock weighs about 8.5 tons, and is approximately two meters high, three meters wide, and one meter thick. It was found in North America and belongs to the National Museum of Mineralogy and Geology, Dresden, Germany. The rock is located at +51°2'34.84" +13°45'26.67".

museum Germany geology
Brachylophosaurus canadensis TMP 1990.104.0001, Oldman Formation, Milk River, Alberta. Original, not cast. At the Royal Tyrrell Museum of Palaeontology.

Brachylophosaurus canadensis TMP 1990.104.0001, Oldman Formation, Milk River, Alberta. Original, not cast. At the Royal Tyrrell Museum of Palaeontology.

museum Milk River Oldman cast +2
Brachylophosaurus canadensis TMP 1990.104.0001, Oldman Formation, Milk River, Alberta. Original, not cast. At the Royal Tyrrell Museum of Palaeontology.

Brachylophosaurus canadensis TMP 1990.104.0001, Oldman Formation, Milk River, Alberta. Original, not cast. At the Royal Tyrrell Museum of Palaeontology.

museum Milk River Oldman cast +2
Title: Dinosaur hunting in western Canada
Identifier: dinosaurhuntingi00russ (find matches)
Year: 1966 (1960s)
Authors: Russell, Loris Shano, 1904-; Royal Ontario Museum
Subjects: Dinosaurs; Paleontology
Publisher: (Toronto : Printed at the University of Toronto Press)
Contributing Library: ROM - University of Toronto
Digitizing Sponsor: University of Toronto

View Book Page: Book Viewer
About This Book: Catalog Entry
View All Images: All Images From Book
Click here to view book online to see this illustration in context in a browseable online version of this book.

Text Appearing Before Image: 
This season of 1921 George Sternberg became the first dinosaur col- lector on the Red Deer River to have his work recorded in motion pictures. This happened by a curious error. The Dominion Motion Picture Bureau, predecessor of the National Film Board of Canada, had decided to make a short motion picture based on the work being done by the Geological Survey of Canada in the collecting and displaying of Canadian dinosaurs. The camera party sent to Alberta was naturally supposed to visit the Geological Survey party under Charles M. Sternberg, but local directions sent them to the camp of George Sternberg. So this excellent little film records field work by the University of Alberta party and preparation being done at the National Museum of Canada in Ottawa. That winter George Sternberg continued the preparation of the speci- mens obtained during the two preceding field seasons, but in the spring he resigned to accept a position with the Field Museum of Natural History of Chicago, under Elmer S. Riggs. The summer of 1922 was the last time that the eldest of the Sternberg sons worked on the Red Deer River, his collec- tion going to Chicago. However, he returned to Edmonton for several months in 1935, to complete the preparation of the collection that he brought together in 1920 and 1921. When George Sternberg left the Geological Survey of Canada in 1918, the only one of the four Sternbergs remaining at Ottawa was Charles Mortram Sternberg, the second son of C. H. Sternberg. Actually, Charles had his first independent expedition to the Red Deer badlands in 1917, C. M. Sternberg ami G. E. Lindblad working on the skull of a horned dinosaur (Centrasaurus sp.), Oldman formation, Red Deer River, 1917. N.M.C., No. 39994.
Text Appearing After Image: 
22

Note About Images

Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original work.

Title: Dinosaur hunting in western Canada Identifier: dinosaurhuntingi00russ (find matches) Year: 1966 (1960s) Authors: Russell, Loris Shano, 1904-; Royal Ontario Museum Subjects: Dinosaurs; Paleontology Publisher: (Toronto : Printed at the University of Toronto Press) Contributing Library: ROM - University of Toronto Digitizing Sponsor: University of Toronto View Book Page: Book Viewer About This Book: Catalog Entry View All Images: All Images From Book Click here to view book online to see this illustration in context in a browseable online version of this book. Text Appearing Before Image: This season of 1921 George Sternberg became the first dinosaur col- lector on the Red Deer River to have his work recorded in motion pictures. This happened by a curious error. The Dominion Motion Picture Bureau, predecessor of the National Film Board of Canada, had decided to make a short motion picture based on the work being done by the Geological Survey of Canada in the collecting and displaying of Canadian dinosaurs. The camera party sent to Alberta was naturally supposed to visit the Geological Survey party under Charles M. Sternberg, but local directions sent them to the camp of George Sternberg. So this excellent little film records field work by the University of Alberta party and preparation being done at the National Museum of Canada in Ottawa. That winter George Sternberg continued the preparation of the speci- mens obtained during the two preceding field seasons, but in the spring he resigned to accept a position with the Field Museum of Natural History of Chicago, under Elmer S. Riggs. The summer of 1922 was the last time that the eldest of the Sternberg sons worked on the Red Deer River, his collec- tion going to Chicago. However, he returned to Edmonton for several months in 1935, to complete the preparation of the collection that he brought together in 1920 and 1921. When George Sternberg left the Geological Survey of Canada in 1918, the only one of the four Sternbergs remaining at Ottawa was Charles Mortram Sternberg, the second son of C. H. Sternberg. Actually, Charles had his first independent expedition to the Red Deer badlands in 1917, C. M. Sternberg ami G. E. Lindblad working on the skull of a horned dinosaur (Centrasaurus sp.), Oldman formation, Red Deer River, 1917. N.M.C., No. 39994. Text Appearing After Image: 22 Note About Images Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original work.

hunting movie museum Canada +1
Brachylophosaurus canadensis skull (original). From the Oldman Formation, Milk River, Alberta. On display at the Royal Tyrrell Museum, Alberta, Canada.

Brachylophosaurus canadensis skull (original). From the Oldman Formation, Milk River, Alberta. On display at the Royal Tyrrell Museum, Alberta, Canada.

museum Canada Milk River Oldman +3
Brachylophosaurus canadensis (TMP 2005.000.0029), Royal Tyrrell Museum, Drumheller, Alberta, 2025-07-13; cast, Campanian, from the Oldman Formation
Formations Oldman

Brachylophosaurus canadensis (TMP 2005.000.0029), Royal Tyrrell Museum, Drumheller, Alberta, 2025-07-13; cast, Campanian, from the Oldman Formation

museum Oldman Campanian cast +2
Psittacosaurus skeletal mount (Early Cretaceous, Jiufotang Formation) and unidentified Late Cretaceous dinosaur egg from Xixia, Hennan, on display in the Li Siguang Memorial Museum in Huangzhou.
Formations Jiufotang

Psittacosaurus skeletal mount (Early Cretaceous, Jiufotang Formation) and unidentified Late Cretaceous dinosaur egg from Xixia, Hennan, on display in the Li Siguang Memorial Museum in Huangzhou.

museum Jiufotang Cretaceous Early Cretaceous +4
Precious opal from Australia. (public display, Denver Museum of Nature & Science, Denver, Colorado, USA)
A mineral is a naturally-occurring, solid, inorganic, crystalline substance having a fairly definite chemical composition and having fairly definite physical properties.  At its simplest, a mineral is a naturally-occurring solid chemical.  Currently, there are over 4900 named and described minerals - about 200 of them are common and about 20 of them are very common.  Mineral classification is based on anion chemistry.  Major categories of minerals are: elements, sulfides, oxides, halides, carbonates, sulfates, phosphates, and silicates.
The silicates are the most abundant and chemically complex group of minerals.  All silicates have silica as the basis for their chemistry.  "Silica" refers to SiO2 chemistry.  The fundamental molecular unit of silica is one small silicon atom surrounded by four large oxygen atoms in the shape of a triangular pyramid - this is the silica tetrahedron - SiO4.  Each oxygen atom is shared by two silicon atoms, so only half of the four oxygens "belong" to each silicon.  The resulting formula for silica is thus SiO2, not SiO4.
Opal is hydrous silica (SiO2·nH2O).  Technically, opal is not a mineral because it lacks a crystalline structure.  Opal is supposed to be called a mineraloid.  Opal is made up of extremely tiny spheres (colloids - <a href="https://www.uwgb.edu/dutchs/acstalks/acscolor/OPALSPHR.jpg" rel="nofollow">www.uwgb.edu/dutchs/acstalks/acscolor/OPALSPHR.jpg</a>) that can be seen with a scanning electron microscope (SEM).
Gem-quality opal, or precious opal, has a wonderful rainbow play of colors (opalescence).  This play of color is the result of light being diffracted by planes of voids between large areas of regularly packed, same-sized opal colloids.  Different opalescent colors are produced by colloids of differing sizes.  If individual colloids are larger than 140 x 10-6 mm in size, purple & blue & green colors are produced.  Once colloids get as large as about 240 x 10-6 mm, red color is seen (Carr et al., 1979).
Not all opals have the famous play of colors, however.  Common opal has a wax-like luster & is often milky whitish with no visible color play at all.  Opal is moderately hard (H = 5 to 6), has a white streak, and has conchoidal fracture.
Several groups of organisms make skeletons of opaline silica, for example hexactinellid sponges, diatoms, radiolarians, silicoflagellates, and ebridians.  Some organisms incorporate opal into their tissues, for example horsetails/scouring rushes and sawgrass.  Sometimes, fossils are preserved in opal or precious opal.
The precious opal shown above is surrounded by silicified claystone.  The rock is from the Griman Creek Formation, a Cretaceous-aged succession of nonmarine, fine-grained and coarse-grained siliciclastic sedimentary rocks.
Stratigraphy: Griman Creek Formation, Albian Stage, upper Lower Cretaceous
Locality: Coocoran Opal Field, west-southwest of Coocoran Lake, northern New South Wales, eastern Australia


Photo gallery of opal:
<a href="http://www.mindat.org/gallery.php?min=3004" rel="nofollow">www.mindat.org/gallery.php?min=3004</a>


References cited:

Carr et al. (1979) - Andamooka opal fields: the geology of the precious stones field and the results of the subsidised mining program.  Geological Survey of South Australia Department of Mines and Energy Report of Investigations 51.  68 pp.

Precious opal from Australia. (public display, Denver Museum of Nature & Science, Denver, Colorado, USA) A mineral is a naturally-occurring, solid, inorganic, crystalline substance having a fairly definite chemical composition and having fairly definite physical properties. At its simplest, a mineral is a naturally-occurring solid chemical. Currently, there are over 4900 named and described minerals - about 200 of them are common and about 20 of them are very common. Mineral classification is based on anion chemistry. Major categories of minerals are: elements, sulfides, oxides, halides, carbonates, sulfates, phosphates, and silicates. The silicates are the most abundant and chemically complex group of minerals. All silicates have silica as the basis for their chemistry. "Silica" refers to SiO2 chemistry. The fundamental molecular unit of silica is one small silicon atom surrounded by four large oxygen atoms in the shape of a triangular pyramid - this is the silica tetrahedron - SiO4. Each oxygen atom is shared by two silicon atoms, so only half of the four oxygens "belong" to each silicon. The resulting formula for silica is thus SiO2, not SiO4. Opal is hydrous silica (SiO2·nH2O). Technically, opal is not a mineral because it lacks a crystalline structure. Opal is supposed to be called a mineraloid. Opal is made up of extremely tiny spheres (colloids - <a href="https://www.uwgb.edu/dutchs/acstalks/acscolor/OPALSPHR.jpg" rel="nofollow">www.uwgb.edu/dutchs/acstalks/acscolor/OPALSPHR.jpg</a>) that can be seen with a scanning electron microscope (SEM). Gem-quality opal, or precious opal, has a wonderful rainbow play of colors (opalescence). This play of color is the result of light being diffracted by planes of voids between large areas of regularly packed, same-sized opal colloids. Different opalescent colors are produced by colloids of differing sizes. If individual colloids are larger than 140 x 10-6 mm in size, purple & blue & green colors are produced. Once colloids get as large as about 240 x 10-6 mm, red color is seen (Carr et al., 1979). Not all opals have the famous play of colors, however. Common opal has a wax-like luster & is often milky whitish with no visible color play at all. Opal is moderately hard (H = 5 to 6), has a white streak, and has conchoidal fracture. Several groups of organisms make skeletons of opaline silica, for example hexactinellid sponges, diatoms, radiolarians, silicoflagellates, and ebridians. Some organisms incorporate opal into their tissues, for example horsetails/scouring rushes and sawgrass. Sometimes, fossils are preserved in opal or precious opal. The precious opal shown above is surrounded by silicified claystone. The rock is from the Griman Creek Formation, a Cretaceous-aged succession of nonmarine, fine-grained and coarse-grained siliciclastic sedimentary rocks. Stratigraphy: Griman Creek Formation, Albian Stage, upper Lower Cretaceous Locality: Coocoran Opal Field, west-southwest of Coocoran Lake, northern New South Wales, eastern Australia Photo gallery of opal: <a href="http://www.mindat.org/gallery.php?min=3004" rel="nofollow">www.mindat.org/gallery.php?min=3004</a> References cited: Carr et al. (1979) - Andamooka opal fields: the geology of the precious stones field and the results of the subsidised mining program. Geological Survey of South Australia Department of Mines and Energy Report of Investigations 51. 68 pp.

museum Australia United States Denver
Precious opal from Australia. (public display, Denver Museum of Nature & Science, Denver, Colorado, USA)
A mineral is a naturally-occurring, solid, inorganic, crystalline substance having a fairly definite chemical composition and having fairly definite physical properties.  At its simplest, a mineral is a naturally-occurring solid chemical.  Currently, there are over 4900 named and described minerals - about 200 of them are common and about 20 of them are very common.  Mineral classification is based on anion chemistry.  Major categories of minerals are: elements, sulfides, oxides, halides, carbonates, sulfates, phosphates, and silicates.
The silicates are the most abundant and chemically complex group of minerals.  All silicates have silica as the basis for their chemistry.  "Silica" refers to SiO2 chemistry.  The fundamental molecular unit of silica is one small silicon atom surrounded by four large oxygen atoms in the shape of a triangular pyramid - this is the silica tetrahedron - SiO4.  Each oxygen atom is shared by two silicon atoms, so only half of the four oxygens "belong" to each silicon.  The resulting formula for silica is thus SiO2, not SiO4.
Opal is hydrous silica (SiO2·nH2O).  Technically, opal is not a mineral because it lacks a crystalline structure.  Opal is supposed to be called a mineraloid.  Opal is made up of extremely tiny spheres (colloids - <a href="https://www.uwgb.edu/dutchs/acstalks/acscolor/OPALSPHR.jpg" rel="nofollow">www.uwgb.edu/dutchs/acstalks/acscolor/OPALSPHR.jpg</a>) that can be seen with a scanning electron microscope (SEM).
Gem-quality opal, or precious opal, has a wonderful rainbow play of colors (opalescence).  This play of color is the result of light being diffracted by planes of voids between large areas of regularly packed, same-sized opal colloids.  Different opalescent colors are produced by colloids of differing sizes.  If individual colloids are larger than 140 x 10-6 mm in size, purple & blue & green colors are produced.  Once colloids get as large as about 240 x 10-6 mm, red color is seen (Carr et al., 1979).
Not all opals have the famous play of colors, however.  Common opal has a wax-like luster & is often milky whitish with no visible color play at all.  Opal is moderately hard (H = 5 to 6), has a white streak, and has conchoidal fracture.
Several groups of organisms make skeletons of opaline silica, for example hexactinellid sponges, diatoms, radiolarians, silicoflagellates, and ebridians.  Some organisms incorporate opal into their tissues, for example horsetails/scouring rushes and sawgrass.  Sometimes, fossils are preserved in opal or precious opal.
The precious opal shown above is surrounded by silicified claystone.  The rock is from the Griman Creek Formation, a Cretaceous-aged succession of nonmarine, fine-grained and coarse-grained siliciclastic sedimentary rocks.
Stratigraphy: Griman Creek Formation, Albian Stage, upper Lower Cretaceous
Locality: Coocoran Opal Field, west-southwest of Coocoran Lake, northern New South Wales, eastern Australia


Photo gallery of opal:
<a href="http://www.mindat.org/gallery.php?min=3004" rel="nofollow">www.mindat.org/gallery.php?min=3004</a>


References cited:

Carr et al. (1979) - Andamooka opal fields: the geology of the precious stones field and the results of the subsidised mining program.  Geological Survey of South Australia Department of Mines and Energy Report of Investigations 51.  68 pp.

Precious opal from Australia. (public display, Denver Museum of Nature & Science, Denver, Colorado, USA) A mineral is a naturally-occurring, solid, inorganic, crystalline substance having a fairly definite chemical composition and having fairly definite physical properties. At its simplest, a mineral is a naturally-occurring solid chemical. Currently, there are over 4900 named and described minerals - about 200 of them are common and about 20 of them are very common. Mineral classification is based on anion chemistry. Major categories of minerals are: elements, sulfides, oxides, halides, carbonates, sulfates, phosphates, and silicates. The silicates are the most abundant and chemically complex group of minerals. All silicates have silica as the basis for their chemistry. "Silica" refers to SiO2 chemistry. The fundamental molecular unit of silica is one small silicon atom surrounded by four large oxygen atoms in the shape of a triangular pyramid - this is the silica tetrahedron - SiO4. Each oxygen atom is shared by two silicon atoms, so only half of the four oxygens "belong" to each silicon. The resulting formula for silica is thus SiO2, not SiO4. Opal is hydrous silica (SiO2·nH2O). Technically, opal is not a mineral because it lacks a crystalline structure. Opal is supposed to be called a mineraloid. Opal is made up of extremely tiny spheres (colloids - <a href="https://www.uwgb.edu/dutchs/acstalks/acscolor/OPALSPHR.jpg" rel="nofollow">www.uwgb.edu/dutchs/acstalks/acscolor/OPALSPHR.jpg</a>) that can be seen with a scanning electron microscope (SEM). Gem-quality opal, or precious opal, has a wonderful rainbow play of colors (opalescence). This play of color is the result of light being diffracted by planes of voids between large areas of regularly packed, same-sized opal colloids. Different opalescent colors are produced by colloids of differing sizes. If individual colloids are larger than 140 x 10-6 mm in size, purple & blue & green colors are produced. Once colloids get as large as about 240 x 10-6 mm, red color is seen (Carr et al., 1979). Not all opals have the famous play of colors, however. Common opal has a wax-like luster & is often milky whitish with no visible color play at all. Opal is moderately hard (H = 5 to 6), has a white streak, and has conchoidal fracture. Several groups of organisms make skeletons of opaline silica, for example hexactinellid sponges, diatoms, radiolarians, silicoflagellates, and ebridians. Some organisms incorporate opal into their tissues, for example horsetails/scouring rushes and sawgrass. Sometimes, fossils are preserved in opal or precious opal. The precious opal shown above is surrounded by silicified claystone. The rock is from the Griman Creek Formation, a Cretaceous-aged succession of nonmarine, fine-grained and coarse-grained siliciclastic sedimentary rocks. Stratigraphy: Griman Creek Formation, Albian Stage, upper Lower Cretaceous Locality: Coocoran Opal Field, west-southwest of Coocoran Lake, northern New South Wales, eastern Australia Photo gallery of opal: <a href="http://www.mindat.org/gallery.php?min=3004" rel="nofollow">www.mindat.org/gallery.php?min=3004</a> References cited: Carr et al. (1979) - Andamooka opal fields: the geology of the precious stones field and the results of the subsidised mining program. Geological Survey of South Australia Department of Mines and Energy Report of Investigations 51. 68 pp.

museum Australia United States Denver
Fossil eggs of the oospecies Macroelongatoolithus carlylei (believed to be the eggs of giant oviraptorosaurs) from the Cedar Mountain Formation of North America. At the SECU Dinolab of the North Carolina Museum of Natural Sciences

Fossil eggs of the oospecies Macroelongatoolithus carlylei (believed to be the eggs of giant oviraptorosaurs) from the Cedar Mountain Formation of North America. At the SECU Dinolab of the North Carolina Museum of Natural Sciences

museum Cedar Mountain fossil Macroelongatoolithus +2
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News

Germany’s Famous Fossil Beds Yield New Species of Jurassic Ichthyosaur
Germany’s Famous Fossil Beds Yield New Species of Jurassic Ichthyosaur
museum Germany Jurassic fossil Ichthyosauria Ichthyosaurus Jabalisaurus new species
Dr. Erin Maxwell from the Staatliches Museum für Naturkunde Stuttgart and colleagues have identified a second species from the German Plattenkalk limestone deposits: Jabalisaurus tethyensis. The post Germany’s Famous Fossil Beds Yield New Species of Jurassic Ichthyosaur appeared first on Sci.News: Breaking Science News.
11/08/2026 sci-news
Scientists rediscover lost Megalodon fossils—and reveal a 79-foot giant
vertebra museum fossil
Several enormous Megalodon vertebrae thought to have been destroyed in 1989 were found sitting unnoticed on a museum shelf. Their analysis strengthens evidence that the giant shark could exceed 24 meters (79 feet) in length and live for nearly a century. Researchers also estimate that its newborns may have measured an astonishing 3.6 meters (12 feet).
07/08/2026 sciencedaily
This school-bus-sized “terror croc” ate dinosaurs. Now it’s back
museum fossil Dinosauria Georgia skeleton
A massive crocodilian capable of attacking dinosaurs has been brought back to life as the first scientifically accurate mounted skeleton of Deinosuchus schwimmeri. The 31-foot replica at Georgia’s Tellus Science Museum was built from detailed fossil scans and more than 40 years of research by paleontologist Dr. David Schwimmer, for whom the species was named.
05/08/2026 sciencedaily
Seal Underwater Hearing Explained by New Research
museum evolution mammals study
A team of international scientists has uncovered the remarkable mechanism behind seal underwater hearing. A new study, led by researchers from the London Natural History Museum reveals how extant seals hear equally well in air and underwater. The findings help to explain a long-standing evolutionary mystery and could support future conservation efforts. The research, published
16/07/2026 everythingdinosaur
Il devient le dinosaure le plus cher du monde en 10 minutes : voici l’incroyable histoire de Gus
He becomes the most expensive dinosaur in the world in 10 minutes: here is Gus' incredible story
museum Dinosauria Tyrannosaurus skeleton
It spent 67 million years buried in the ground before shaking an auction house. The skeleton of Tyrannosaurus rex nicknamed “Gus” was sold for $50.13 million at Sotheby’s in New York. An absolute record for a dinosaur, which revives the debate on the privatization of...
15/07/2026 futura-terre ⚙ Auto-translated
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