Size: 9x6x1" - 5 Lbs.
Color: Clear/White Quartz Crystal - Natural Color
Locality: Minas Gerais, Brazil
This sale is for the natural color, large Brazilian quartz crystal geode slab pictured. This large slice would make an Christmas gift, as a nice display specimen or for a multitude of other projects. This piece is also wall-mountable. Please feel free to contact us if you have any special requests - we are happy to assist you.
GEODE PROPERTIES:
A geode is a geological secondary formation within sedimentary and volcanic rocks. Geodes are hollow, vaguely spherical rocks, in which masses of mineral matter (which may include crystals) are secluded. The crystals are formed by the filling of vesicles in volcanic and sub-volcanic rocks by minerals deposited from hydrothermal fluids; or by the dissolution of syn-genetic concretions and partial filling by the same, or other, minerals precipitated from water, groundwater or hydrothermal fluids. Geodes can form in any cavity, but the term is usually reserved for more or less rounded formations in igneous and sedimentary rocks. They can form in gas bubbles in igneous rocks, such as vesicles in basaltic lava; or, as in the American Midwest, in rounded cavities in sedimentary formations. After rock around the cavity hardens, dissolved silicates and/or carbonates are deposited on the inside surface. Over time, this slow feed of mineral constituents from groundwater or hydrothermal solutions allows crystals to form inside the hollow chamber. Bedrock containing geodes eventually weathers and decomposes, leaving them present at the surface if they are composed of resistant material such as quartz. When cut in half, visible bands corresponding to varied stages of precipitation may at times show patterns that reveal points of fluid entry into the cavity and/or varied colors corresponding to changes in chemistry.
Geodes are common in some formations in the United States (mainly in Indiana, Iowa, Missouri, western Illinois, Kentucky, and Utah). In Oregon they are referred to as thundereggs (which are normally completely filled solid) and are the Oregon State Rock. They also are common in Brazil, Namibia, and Mexico.
Courtesy of Wikipedia
Color: Clear/White Quartz Crystal - Natural Color
Locality: Minas Gerais, Brazil
This sale is for the natural color, large Brazilian quartz crystal geode slab pictured. This large slice would make an Christmas gift, as a nice display specimen or for a multitude of other projects. This piece is also wall-mountable. Please feel free to contact us if you have any special requests - we are happy to assist you.
A geode is a geological secondary formation within sedimentary and volcanic rocks. Geodes are hollow, vaguely spherical rocks, in which masses of mineral matter (which may include crystals) are secluded. The crystals are formed by the filling of vesicles in volcanic and sub-volcanic rocks by minerals deposited from hydrothermal fluids; or by the dissolution of syn-genetic concretions and partial filling by the same, or other, minerals precipitated from water, groundwater or hydrothermal fluids. Geodes can form in any cavity, but the term is usually reserved for more or less rounded formations in igneous and sedimentary rocks. They can form in gas bubbles in igneous rocks, such as vesicles in basaltic lava; or, as in the American Midwest, in rounded cavities in sedimentary formations. After rock around the cavity hardens, dissolved silicates and/or carbonates are deposited on the inside surface. Over time, this slow feed of mineral constituents from groundwater or hydrothermal solutions allows crystals to form inside the hollow chamber. Bedrock containing geodes eventually weathers and decomposes, leaving them present at the surface if they are composed of resistant material such as quartz. When cut in half, visible bands corresponding to varied stages of precipitation may at times show patterns that reveal points of fluid entry into the cavity and/or varied colors corresponding to changes in chemistry.
Geodes are common in some formations in the United States (mainly in Indiana, Iowa, Missouri, western Illinois, Kentucky, and Utah). In Oregon they are referred to as thundereggs (which are normally completely filled solid) and are the Oregon State Rock. They also are common in Brazil, Namibia, and Mexico.
Courtesy of Wikipedia