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Allophane, is more of an amorphous to crystalline mineraloid form of crystalline or Amorphous Hydrous Silicate of aluminium than a mineral per se. It is best identified by its distinct infrared spectrum and X-ray diffraction pattern. It was in 1816, in Germany, that Allophane was first described. Having a pH value of 5-7, the clay-like Allophane more or less thrived only in a mildly acidic environment. It has an amorphous crystal structure and waxy luster. The color of Allophane may vary from white, green, brown to blue.
Chemical Formula
Al2O3· (SiO2) 1.3-2· (2.5-3) H2O
Derivation Of Name
Allopane is a Greek word. In Greek, “Allos”means other and “Phanos” means to appear, meaning, this mineral gives a deceptive reaction when it tested in a blowpipe flame.
Occurrence
The Allophane mineral is a hydrothermal alteration product of “weathering, ” resulting from the breakdown of mineral, soil and rock (feldspars and volcanic glass) in a condition of no movement or “in situ”, and is best not confused with erosion.
Gemology
The gemstone of this rare mineraloid varies from light to dark hues. Colorful specimen exist of bright blue Azurite inter-grown with translucent green.
Amazonite is a popular collector’s item and also used in jewelry It is usually light green to blue- green and is found in granite and pegmatites.
Source
The major source of Allophane mineral is in Germany, at the mines of the Rieche, Saxony and Himmelfahrt, and in the districts of Freiberg and Erzgebirge
Mineralogy
It is the main member of "Allophane Group." In aqueous conditions, it can be altered to form Halloysite and in desilicating conditions, it can form Gibbsite. It also contains a variety of Cupro-Allophane.
Color
White, brown, green, yellowish blue to sky-blue.
Density 3 g/cm3
Hardness: 5 to 6 on the Mohs Scale.
Main Applications
Allophane’s low cost, combined with its environmentally friendly features renders it as a highly sought after product used in the remediation process of both phosphorous rich water effluent and euphoric waters.
The Mythical
This stone is said to promote balance, enhance stability and sociability skills. It is also known for protecting the eyes and glands.
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