Mineral Beudantite
The chemical composition of mineral Beudantite is indicated by the formula PbFe3AsO4SO4(OH)6, a Lead Iron Arsenate Sulfate Hydroxide. This Beudantite belongs to the Sulfates mineral class. Sulfates are known chemically to contain the sulfate anion with a charge of negative two. This mineral class commonly forms in evaporitic settings where evaporation of water with high saline content slowly occurs. Through this process, the formation of both halides and sulfates are allowed at the water-sediment interface. Sulfate minerals are known to commonly occur as gauge minerals in some hydrothermal veins systems along with sulfide ore minerals. These Sulfide ore minerals are commonly found exhibiting brilliant microscope image under an ore polarizing light microscope. They can be also formed as a secondary oxidation product of original sulfide minerals. The Sulfates class commonly includes minerals exhibiting interesting and attractive mineral specimens, which are usually splendid when viewed with the aid of petrographic polarizing light microscope. A typical sulfate mineral is usually vitreous in luster, with average hardness in Mohs scale, and usually has density that is considered average to above average. Some Sulfates are usually soluble and fluorescent in ultraviolet light.
Beudantite minerals are sometimes classified as Phosphates. 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 polarizing light 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.
Beudantite mineral is considered very hard to classify if it is a sulfate or a phosphate. This is because it has both a sulfate anion group and an arsenate anion group. The presence of the arsenate anion group in the chemical structure of Beudantite would readily suggest that it would be under the classification of the Arsenate Group of the Phosphate Class of minerals. But the sulfate anion group of Beudantite is really intricate and is really essential in its structure. While the arsenate anion group on the other hand can be found being substituted for by a phosphate anion group to at least a limited degree. However, there are many classification schemes that placed Beudantite minerals under the Phosphate mineral class. Beudantite specimens are considered at times as very attractive minerals in the mineral world. Sometimes they can be found beautifully colored in transmitted light of polarizing light microscope for geologist, although they often appear too dark and almost appearing black. Beudantite minerals are usually found exhibiting nice luster in reflected light of petrographic polarizing microscope due to its lead content. They are commonly found associated with other secondary minerals that are very rare, which are usually found in the oxidation zones of ore deposit. These assorted mineral specimens being the result of the marvelous mineral association can be quite interesting to view under geological microscope, and are commonly considered a bonus to most mineral collectors who certainly like a lot of different minerals on one specimen.
Beudantite mineral was first discovered in the year 1826 at the Louise Mine in Germany. Beudantite mineral species was named after Francois Sulpice Beudant (1787-1850), a French mineralogist and physicist who worked at the University of Paris. Beudantite mineral actually lends its name from a group of sulfate-phosphates and sulfate-arsenates that is called the Beudantite Group. This group actually comprises minerals that are trigonal crystal formation and are commonly found containing a sulfate ion group and are also usually found having six hydroxides. The Beudantite group of minerals is usually having the general formula that is commonly indicated by AB3{AsO4 and/or PO4}SO4(OH)6. The A cation can stand to be barium, calcium, strontium, cerium, lead and/or hydrogen. The B cation on the other hand can stand to be iron, gallium, and/or aluminum.
Mineral specimen Beudantite are commonly found in shades of green, dark green, orange-brown, yellow-brown, brown or black in transmitted light of polarizing light microscope for geologists. Beudantite mineral is commonly found exhibiting a variety of luster in reflected light of geological polarizing microscope. It usually has perfect basal cleavage or a perfect cleavage when evaluated under a geological polarizing microscope that is often found in only one direction. But cleavage planes are not really visible always. It has conchoidal fracture found between crossed nicols of petrographic polarizing light microscope. The hardness measure of Beudantite using the Mohs scale method usually gives a value of 4. When mineral specimen Beudantite is rubbed on a white streak plate, it usually leaves a greenish yellow streak. The specific gravity measure of Beudantite mineral usually gives an approximate value usually ranging from 4.3g/cm³ to 4.5g/cm³, which is commonly considered heavy for non-metallic minerals.
Beudantite minerals are known to crystallize in the trigonal system, which is clearly visible when the specimen is evaluated with the aid of geological microscope. Beudantite mineral specimens are commonly found transparent to translucent in appearance. Crystal habits of Beudantite minerals commonly include blocky rhombohedrons and platy to tabular crystals, which are clearly visible under geological polarizing light microscopes. The blocky rhombohedrals are commonly found having a crystal shape that resembles rhombohedrons that are seen clearly with the aid of petrographic polarizing microscope. Tabular crystals are usually found as shaped like book that are splendidly exhibited under a polarizing microscope for geologists. Beudantite can be also found as very thin pseudohexagonal platelets, which are interesting to view under polarizing microscopes. Sometimes Beudantite can be also found in pseudo-cubic forms, also as druses, earthy masses and crusts. Beudantite can be also found in druse forms. Druses are usually the crystal growth in a cavity, which commonly results in numerous crystal tipped surfaces. Some mineral specimen Beudantite appears fairly amorphous but when they are magnified with the aid of a geological microscope, some small pseudocubic crystals can be found visible. Crystals of Beudantite mineral usually display a wide range of colors when evaluated under polarized light microscope. Beudantite crystals are usually brittle, a property that is generally displayed by glasses and most non-metallic minerals. Beudantite minerals are commonly associated with several other interesting minerals such as mimetite, conichalcite, jarosite, galena, arsenopyrite, anglesite, sphalerite, pyrrhotite, aegirine, pyrite, descloizite, microcline, tetranatrolite, hemimorphite, muscovite, natrolite and arthurite.
Beudantite minerals are actually uniaxial negative figures under polarizing light microscope for geologists. Beudantite minerals are actually found non-radioactive after several chemical evaluations. Refractive indices of Beudantite minerals are usually found ranging from 1.957 to 1.943. Beudantite minerals are usually found having very high surface relief when specimen is viewed between crossed nicols of petrographic polarizing light microscope. There is no specific data on the toxicity and health dangers for mineral specimen Beudantite. However, Beudantite minerals should be treated with great care and use of sensible precaution is advised upon handling them.
Beudantite minerals are often found in the second oxidation zones. They are actually considered secondary minerals in the oxidation zone of polymetallic deposits. The best field indicators of mineral beudantite usually include color, streak, hardness, crystal habit, luster and density. Beudantite minerals are notably found at some types of localities that usually include Australia, Namibia, Greece, Canada and some areas in the United States like several mines found in Arizona.
