A chemically pure and structurally perfect diamond is perfectly transparent with no hue, or color. However, in reality almost no gem-sized natural diamonds are absolutely perfect. The color of a diamond may be affected by chemical impuritiesand/or structural defects in the crystal lattice. Depending on the hue and intensity of a diamond’s coloration, a diamond’s color can either detract from or enhance its value. For example, most white diamonds are discounted in price when more yellow hue is detectable, while intense pink diamonds or blue diamonds (such as the Hope Diamond) can be dramatically more valuable. Of all colored diamonds, red diamonds are the rarest. The Aurora Pyramid of Hope displays a spectacular array of naturally colored diamonds, including red diamonds.
When placed between two polarizing filters set at right angles to each other, the optical properties of the minerals in the thin section alter the colour and intensity of the light as seen by the viewer. As different minerals have different optical properties, most rock forming minerals can be easily identified. Plagioclase for example can be seen in the photo on the right as a clear mineral with multiple parallel twinning planes. The large blue-green minerals are clinopyroxene with some exsolution of orthopyroxene.
Thin sections are prepared in order to investigate the optical properties of the minerals in the rock. This work is a part of petrology and helps to reveal the origin and evolution of the parent rock.
A photograph of a rock in thin section is often referred to as a photomicrograph.
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A chemically pure and structurally perfect diamond is perfectly transparent with no hue, or color. However, in reality almost no gem-sized natural diamonds are absolutely perfect. The color of a diamond may be affected by chemical impuritiesand/or structural defects in the crystal lattice. Depending on the hue and intensity of a diamond’s coloration, a diamond’s color can either detract from or enhance its value. For example, most white diamonds are discounted in price when more yellow hue is detectable, while intense pink diamonds or blue diamonds (such as the Hope Diamond) can be dramatically more valuable. Of all colored diamonds, red diamonds are the rarest. The Aurora Pyramid of Hope displays a spectacular array of naturally colored diamonds, including red diamonds.
When placed between two polarizing filters set at right angles to each other, the optical properties of the minerals in the thin section alter the colour and intensity of the light as seen by the viewer. As different minerals have different optical properties, most rock forming minerals can be easily identified. Plagioclase for example can be seen in the photo on the right as a clear mineral with multiple parallel twinning planes. The large blue-green minerals are clinopyroxene with some exsolution of orthopyroxene.
Thin sections are prepared in order to investigate the optical properties of the minerals in the rock. This work is a part of petrology and helps to reveal the origin and evolution of the parent rock.
A photograph of a rock in thin section is often referred to as a photomicrograph.
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Salvinia, a genus in the family Salviniaceae, is a floating fern named in honor of Anton Maria Salvini, a 17th-century Italian scientist. Watermoss is a common name for Salvinia.[1] The genus was published in 1754 by Jean-François Séguier, in his description of the plants found round Verona, Plantae Veronenses[2] Twelve species are recognized, at least three of which (S. molesta, S. herzogii, and S. minima) are believed to be hybrids, in part because their sporangia are found to be empty.
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A fern is a member of a group of vascular plants that reproduce via spores and have neither seeds nor flowers. They differ from mosses by being vascular, i.e., having certain tissue that conducts water and nutrients, and having branched stems. Like other vascular plants, ferns have leaves, and these are “megaphylls”, which are more complex than the “microphylls” of clubmosses. Most ferns are leptosporangiate ferns, sometimes termed “true ferns”; they produce what are called “fiddleheads” that uncoil and expand into fronds.[3] The group includes about 10,560 known extant species.[4]
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A fern is a member of a group of vascular plants that reproduce via spores and have neither seeds nor flowers. They differ from mosses by being vascular, i.e., having certain tissue that conducts water and nutrients, and having branched stems. Like other vascular plants, ferns have leaves, and these are “megaphylls”, which are more complex than the “microphylls” of clubmosses. Most ferns are leptosporangiate ferns, sometimes termed “true ferns”; they produce what are called “fiddleheads” that uncoil and expand into fronds.[3] The group includes about 10,560 known extant species.[4]
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Azolla (mosquito fern, duckweed fern, fairy moss, water fern) is a genus of seven species of aquaticferns in the family Salviniaceae. They are extremely reduced in form and specialized, looking nothing like other typical ferns but more resembling duckweedor some mosses.
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A fern is a member of a group of vascular plants that reproduce via spores and have neither seeds nor flowers. They differ from mosses by being vascular, i.e., having certain tissue that conducts water and nutrients, and having branched stems. Like other vascular plants, ferns have leaves, and these are “megaphylls”, which are more complex than the “microphylls” of clubmosses. Most ferns are leptosporangiate ferns, sometimes termed “true ferns”; they produce what are called “fiddleheads” that uncoil and expand into fronds.[3] The group includes about 10,560 known extant species.[4]
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Azolla (mosquito fern, duckweed fern, fairy moss, water fern) is a genus of seven species of aquaticferns in the family Salviniaceae. They are extremely reduced in form and specialized, looking nothing like other typical ferns but more resembling duckweedor some mosses.
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Salvinia, a genus in the family Salviniaceae, is a floating fern named in honor of Anton Maria Salvini, a 17th-century Italian scientist. Watermoss is a common name for Salvinia.[1] The genus was published in 1754 by Jean-François Séguier, in his description of the plants found round Verona, Plantae Veronenses[2] Twelve species are recognized, at least three of which (S. molesta, S. herzogii, and S. minima) are believed to be hybrids, in part because their sporangia are found to be empty.
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Salvinia, a genus in the family Salviniaceae, is a floating fern named in honor of Anton Maria Salvini, a 17th-century Italian scientist. Watermoss is a common name for Salvinia.[1] The genus was published in 1754 by Jean-François Séguier, in his description of the plants found round Verona, Plantae Veronenses[2] Twelve species are recognized, at least three of which (S. molesta, S. herzogii, and S. minima) are believed to be hybrids, in part because their sporangia are found to be empty.
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This product has multiple variants. The options may be chosen on the product page
Salvinia, a genus in the family Salviniaceae, is a floating fern named in honor of Anton Maria Salvini, a 17th-century Italian scientist. Watermoss is a common name for Salvinia.[1] The genus was published in 1754 by Jean-François Séguier, in his description of the plants found round Verona, Plantae Veronenses[2] Twelve species are recognized, at least three of which (S. molesta, S. herzogii, and S. minima) are believed to be hybrids, in part because their sporangia are found to be empty.
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Azolla (mosquito fern, duckweed fern, fairy moss, water fern) is a genus of seven species of aquaticferns in the family Salviniaceae. They are extremely reduced in form and specialized, looking nothing like other typical ferns but more resembling duckweedor some mosses.
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Eye liner was first used in Ancient Egypt and Mesopotamia as a dark black line around the eyes. As early as 10,000 BC, Egyptians and Mo wore various cosmetics including eye liner not only for aesthetics but to protect the skin from the desert sun. Research has also speculated that eye liner was worn to protect the wearer from the evil eye. The characteristic of having heavily lined eyes has been frequently depicted in ancient Egyptian art. They produced eye liner with a variety of materials, including copper ore and antimony. Ancient Egyptian kohl contained galena, which was imported from nearby regions in the Land of Punt, Coptos and Western Asia.[1]
In the 1920s, Tutankhamun‘s tomb was discovered, introducing the use of eye liner to the Western world. The 1920s were an era commonly associated with many changes in women’s fashion, and women felt freer to apply make-up more liberally.
In the 1960s, liquid eye liner was used to create thick black and white lines around the eyes in the make-up fashion associated with designers like Mary Quant.
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Eye liner was first used in Ancient Egypt and Mesopotamia as a dark black line around the eyes. As early as 10,000 BC, Egyptians and Mo wore various cosmetics including eye liner not only for aesthetics but to protect the skin from the desert sun. Research has also speculated that eye liner was worn to protect the wearer from the evil eye. The characteristic of having heavily lined eyes has been frequently depicted in ancient Egyptian art. They produced eye liner with a variety of materials, including copper ore and antimony. Ancient Egyptian kohl contained galena, which was imported from nearby regions in the Land of Punt, Coptos and Western Asia.[1]
In the 1920s, Tutankhamun‘s tomb was discovered, introducing the use of eye liner to the Western world. The 1920s were an era commonly associated with many changes in women’s fashion, and women felt freer to apply make-up more liberally.
In the 1960s, liquid eye liner was used to create thick black and white lines around the eyes in the make-up fashion associated with designers like Mary Quant.
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This product has multiple variants. The options may be chosen on the product page
Eye liner was first used in Ancient Egypt and Mesopotamia as a dark black line around the eyes. As early as 10,000 BC, Egyptians and Mo wore various cosmetics including eye liner not only for aesthetics but to protect the skin from the desert sun. Research has also speculated that eye liner was worn to protect the wearer from the evil eye. The characteristic of having heavily lined eyes has been frequently depicted in ancient Egyptian art. They produced eye liner with a variety of materials, including copper ore and antimony. Ancient Egyptian kohl contained galena, which was imported from nearby regions in the Land of Punt, Coptos and Western Asia.[1]
In the 1920s, Tutankhamun‘s tomb was discovered, introducing the use of eye liner to the Western world. The 1920s were an era commonly associated with many changes in women’s fashion, and women felt freer to apply make-up more liberally.
In the 1960s, liquid eye liner was used to create thick black and white lines around the eyes in the make-up fashion associated with designers like Mary Quant.
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This product has multiple variants. The options may be chosen on the product page
Many pencils across the world, and almost all in Europe, are graded on the European system using a continuum from H (commonly interpreted as “hardness”) to B (commonly “blackness”), as well as F (usually taken to mean “fineness”, although F pencils are no more fine or more easily sharpened than any other grade. also known as “firm” in Japan[45]). The standard writing pencil is graded HB.[46]
According to Petroski, this system might have been developed in the early 20th century by Brookman, an English pencil maker. It used B for black and H for hard; a pencil’s grade was described by a sequence or successive Hs or Bs such as BB and BBB for successively softer leads, and HH and HHH for successively harder ones.[47]
The Koh-i-Noor Hardtmuth pencil manufacturers claim to have originated the HB standard of gradations, with H standing for Hardtmuth, B for the company’s location of Budějovice, and F for Franz Hardtmuth, who was responsible for technological improvements in pencil manufacture.[48][49]
