Mineral Augelite
The chemical composition of the mineral Augelite is indicated by the formula Al2PO4(OH)3, Aluminum Phosphate Hydroxide. This Augelite belongs to the Phosphate mineral class. The Phosphates group of minerals commonly includes all minerals having a tetrahedral unit indicated by the formula AO4 with a negative three charge, where A can stand to be either antimony, arsenic, phosphorus or vanadium. The basic tetrahedral unit can be combined with other metal ions on a one to one ratio. Usually, it can be found in a more complex combinations with other ions such as the hydroxide groups with formula indicated by (OH), the uranyl groups with formula indicated by (UO2), a halogen or even water molecules. Apatite mineral is the most common phosphate, of which it is considered as an important biological mineral that is commonly found present in the teeth and bones of many animals. A typical phosphate mineral usually exhibits vitreous to dull luster in reflected light of polarizing microscope. Phosphate mineral specimens are often found strongly colored with density measure that is usually above average. The index of refraction found between crossed nicols of geological light polarizing microscope is usually low. The hardness found for most phosphate minerals is commonly at an average ranging from 4 to 7. Some other characteristics and properties vary for each kind of mineral.
Augelite, although a Phosphate, is actually not a very well known mineral. When Augelite specimens appear in tiny colorless and clear crystals, they are actually difficult to recognize. The White Mountain, Mono County in California is considered as the best location for Augelite mineral having good crystal formations. Up until the time of the first discovery, Augelite mineral is commonly known having tiny crystals and cleavage masses. Augelite mineral is commonly associated with other minerals including andalusite, triphylite, lithiophilite, pyrite and other phosphates. Augelite is only used as a mineral specimen. One specimen found in San Jose Mine, Oruro City, Cercado Province, Oruro Department, Bolivia exhibiting nice combination consisting iridescent brassy to reddish purple to purple crystals of pyrite mineral, which is found covering most crystal parts of colorless glassy Augelite mineral. This marvelous and neat combination piece exhibits splendid microscope image under petrographic light polarizing microscope.
Mineral Augelite derived its name from a Greek word “auge”, which means bright or luster. This is an allusion to its pearly luster that is exhibited on the cleavage, which can be found visible with the aid of geological polarizing microscope. This mineral species Augelite was first discovered in the year 1868 at Vestana Iron Mine, Nasum, Skane in Sweden.
Augelite mineral specimens are commonly found exhibiting shades of white or pale shades of blue pink, yellow or rose in transmitted light of petrographic light polarizing microscope. Crystals of Augelite may also appear colorless, which allows all constituents of white light to pass through making the mineral non-pleochroic even in crossed nicols of polarized microscopes. When this mineral specimen Augelite is rubbed on a white streak plate, it commonly leaves a white streak. Augelite mineral specimens commonly show vitreous luster in reflected light of light polarizing microscope. It also exhibits pearly luster on its cleavage. The hardness measure of Augelite mineral using the Mohs scale method is usually ranging from 4.5 to 5.0, which is commonly considered insignificant and not really suitable for gemstone purposes. The cleavage found between crossed nicols of polarized light microscope is commonly found in two directions. In one direction, the cleavage found is usually perfect, and only good at the other direction. Fracture found under several adjustments on the aperture diaphragm of geological polarizing microscope is commonly conchoidal. A smooth curved fracture with concentric ridges of the type shown by glass is exhibited under the polarizing microscope. Fracture describes how a mineral breaks when broken contrary to its natural cleavage planes. Crystals of Augelite are actually considered brittle, a property that is generally displayed by glasses and most non-metallic minerals. The specific gravity measure of Augelite mineral specimen is usually found in an approximate value of 2.7g/cm³, which is generally considered average.
Augelite minerals are known to crystallize in a monoclinic system. The monoclinic system of crystal formation comprises crystals having three axes of unequal lengths. Two of which are usually found in a position that is oblique or not perpendicular to one another. However, both of which are commonly found perpendicular to the third axis. Specimens of Augelite commonly appear transparent. Some specimens can be also found in translucent appearance. Augelite minerals commonly form prismatic crystals in transmitted light of polarized microscopes. Crystals in prismatic form are usually having dominant faces of those of a prism. Crystal habits of Augelite usually include tiny to microscopic tabular or platy crystals. Tabular crystals usually display a shape like a book. It commonly displays an overall triangular aspect or larger equant complex crystals, which are majestically exhibited under light polarizing microscopes for geologists. Equant is a form of equidimensional grains. This Augelite mineral is sometimes found in massive forms.
This mineral Augelite is commonly considered having a positive biaxial figure between crossed nicols of light polarizing microscopes. After chemical evaluations, this mineral Augelite is found to be not radioactive. When Augelite mineral specimens are evaluated with the aid of petrographic light polarizing microscope, it can be found having low surface relief. It has no dispersion found between crossed nicols of polarized microscopes. There are no specific data on toxicity and health dangers for mineral Augelite. However, specimens of this mineral should be treated with great care and use of sensible precautions is recommended upon handling them.
Augelite mineral specimens are usually found in granitic pegmatites. They commonly form in hydrothermal veins. It can be also formed by hydrogen metamorphism of phosphate-bearing rocks in peraluminous sediments. It can be also found in some high-temperature hydrothermal ore deposits. Best field indicators of mineral Augelite usually include color, crystal habit, cleavage, localities, and its splendid associations with other minerals. Notable occurrences of mineral Augelite commonly include types of localities such as White Picacho district, Arizona; Rapid Creek, Yukon Territory, Canada; Oruro, Bolivia; North Groton, New Hampshire; Vestana Mine, Nastum, Skane and at Kalsjoberg, Varmland, Sweden. Augelite minerals in good crystal forms are commonly found in the Black Hills region of South Dakota and most especially at White Mountain, Mono County, California in the United States of America.
