The chemical composition of mineral Delvauxite is indicated by the formula CaFe+++4(PO4,SO4)2(OH)8•4-6(H2O). This mineral is commonly found occurring in a gossan. It can be also found from its type of locality at Berneau, near Vise, Liège, Belgium. Delvauxite was named after J.S.P.J. Delvaux de Feuffe (1782-1863), Belgian chemist who first described and analyzed the mineral. Mineral Delvauxite is known to be amorphous. It has no cleavage displayed even when closely evaluated with the aid of polarized microscope. Delvauxite is commonly found in shades of yellowish brown, brown, reddish brown or brownish black in hand sample. The density measure of mineral Delvauxite is usually found ranging from 1.8 to 2 grams per cubic centimeters, with an average of 1.9. Delvauxite is also found to show conchoidal fractures developed in brittle materials characterized by smoothly curving surfaces, similar to quartz. Delvauxite is known to be amorphous or without any crystalline form or imitative shape. Sometimes it can be concretionary showing rounded massive fine-grained materials. Mineral Delvauxite is also found to be stalactitic or shaped like pendant columns as stalactites or stalagmites similar to calcite. The hardness measure of mineral Delvauxite is usually found 2.5 when evaluated using the Mohs scale method. Delvauxite is also exhibiting vitreous to greasy luster in reflected light of petrographic polarizing microscope. It is also commonly found leaving yellow streak when rubbed on white porcelain streak plate. Delvauxite is known be an isotropic mineral. Mineral Delvauxite is also found not radioactive after chemically evaluated.
Tuesday, January 31st, 2012 at 4:50 am
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