Bivalve borings in fossil wood from the Cretaceous of Australia. (public display, Gorman Nature Center, Mansfield, Ohio, USA)
The dark material in this specimen is quartz-permineralized, araucariacean conifer wood. The rounded and elongated areas within the wood are borings (drill holes) called Teredolites. The borings were made by "shipworm" bivalves that specialize in drilling into wood (see: en.wikipedia.org/wiki/Teredo_navalis). The light-colored fill in the borings is radiolarite, a siliceous sedimentary rock formed by lithification of radiolarian-rich sediments. (see: en.wikipedia.org/wiki/Radiolaria). The host rock for the fossil wood is radiolarite.
Rockhounds call this material "peanut wood".
Classification of trace makers: Animalia, Mollusca, Bivalvia, Heterodonta, Myoida, Teredinidae
Classification of wood: Plantae, Pinophyta, Pinopsida, Pinales, Araucariaceae
Stratigraphy: Windalia Radiolarite, Aptian to Albian Stages, upper Lower Cretaceous
Locality: Mooka Creek area, Kennedy Ranges, Western Australia
Tags: Teredolites fossil fossils boring borings Teredo bivalve bivalves Windalia Radiolarite Cretaceous Mooka Creek Kennedy Ranges Western Australia peanut wood petrified permineralized
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Tags: Gorman Nature Center Mansfield Richland County Ohio
Quartz crystals lining geode from Morocco. (public display, Gorman Nature Center, Mansfield, Ohio, 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 6000 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.
The simplest & most abundant silicate mineral in the Earth's crust is quartz (SiO2). All other silicates have silica + impurities. Many silicates have a significant percentage of aluminum (the aluminosilicates).
Quartz (silicon dioxide/silica - SiO2) is the most common mineral in the Earth's crust. It is composed of the two most abundant elements in the crust - oxygen and silicon. It has a glassy, nonmetallic luster, is commonly clearish to whitish to grayish in color, has a white streak, is quite hard (H≡7), forms hexagonal crystals, has no cleavage, and has conchoidal fracture. Quartz can be any color: clear, white, gray, black, brown, pink, red, purple, blue, green, orange, etc.
Geodes small to large, subspherical to irregularly-shaped, crystal-lined cavities in rocks. They form when water enters a void in a host rock and precipitates crystals. The most common geode-lining mineral is quartz. The reddish coloration of the quartz lining the Moroccan geode shown above is from iron oxide (hematite) impurities.
Locality: unrecorded/undisclosed site in the Atlas Mountains of Morocco
Tags: quartz crystal crystals silica silicates silicate mineral minerals geode geodes Atlas Mountains Morocco
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Tags: Gorman Nature Center Mansfield Richland County Ohio
Quartz crystals from Romania. (public display, Gorman Nature Center, Mansfield, Ohio, 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 6000 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.
The simplest & most abundant silicate mineral in the Earth's crust is quartz (SiO2). All other silicates have silica + impurities. Many silicates have a significant percentage of aluminum (the aluminosilicates).
Quartz (silicon dioxide/silica - SiO2) is the most common mineral in the Earth's crust. It is composed of the two most abundant elements in the crust - oxygen and silicon. It has a glassy, nonmetallic luster, is commonly clearish to whitish to grayish in color, has a white streak, is quite hard (H≡7), forms hexagonal crystals, has no cleavage, and has conchoidal fracture. Quartz can be any color: clear, white, gray, black, brown, pink, red, purple, blue, green, orange, etc.
The greenish color of the quartz crystals shown above is from chlorite inclusions.
Locality: unrecorded/undisclosed site in Transylvania, Romania
Tags: quartz crystal crystals silica silicates silicate mineral minerals chlorite Transylvania Romania