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Click Here For Best Selection Of High Quality Polarizing Microscope

Click Here For Best Selection Of High Quality Polarizing Microscope

The chemical formula (Na, Ca)4(Fe++, Ti, Mg)12Si12O40. A primary constituent in sodium-rich alkali volcanic, pegmatites, and other silica-poor igneous rocks. Aenigmatite notably occur at localities including Naujakasik, near the Tunugdliarfik Fjord, and on the Kangerdluarssuk Plateau, in the Ilimaussaq intrusion; from Narssarssuk; and elsewhere. The name of the mineral Aenigmatite was derived from the Greek word for riddle, apparently an allusion to its formerly uncertain chemical composition. The mineral is known to crystallize in the triclinic system of crystal formation. In optical mineralogy, this triclinic crystal system commonly comprises crystals having three axes, of which all are unequal in length and are positioned oblique to one another. Mineral Aenigmatite is usually found showing perfect cleavage in one direction which can be seen more clearly exhibited when viewed with the aid of polarizing light microscope used in the optical mineralogy. Mineral Aenigmatite is usually found exhibiting brown or black color. The specific gravity measure of the mineral is usually ranging 3.74 to 3.85 grams per cubic centimeters. Most crystals of mineral Aenigmatite are found opaque in appearance. They are also most commonly found forming lamellar crystal forms or thin laminae producing a lamellar structure. The hardness measure of the mineral when it is evaluated using the Mohs scale method is between 5 to 6. This mineral is non-fluorescent and it is usually found showing subadamantine luster when viewed in reflected light of polarizing microscopes used in optical mineralogy. Aenigmatite is most commonly found leaving a reddish brown streak when specimen is rubbed on a white porcelain streak plate. Aenigmatite is also commonly found showing biaxial positive figure when viewed between crossed nicols of polarized microscopes.. The birefringence of the mineral is usually found 0.0900 to 0.1000. The dispersion angle is usually between 27- to 55-degree. Aenigmatite is usually found pleochroic in light brown, brown to dark brown color. Aenigmatite is a non-radioactive mineral.



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Saturday, February 27th, 2010 at 9:27 am
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Optical Mineralogy
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Click Here For Best Selection Of High Quality Polarizing Microscope