The chemical composition of the mineral Lollingite is indicated by the formula FeAs2, an Iron Arsenide. This Lollingite belongs to the Sulfides mineral class. It is also a member of the Marcasite and Lollingite mineral groups. Mineral Lollingite is commonly considered as a minor ore of arsenic and as a mineral specimen it is most commonly found exhibiting a nice and fascinating appearance when viewed with the aid of geological polarizing light microscopes. Mineral Lollingite is also commonly used as mineral specimen and it is often found displaying a nice and interesting microscope image under petrographic polarizing microscope. Mineral Lollingite is sometimes spelled as loellingite. This mineral species is very uncommon but it can be also found with other arsenides. Thus it is included with them when mined for arsenic. The chemical formula of mineral Lollingite is never exactly FeAs2. This is because it usually contains significant percentage of cobalt and nickel and also sometimes sulfur.
Mineral Lollingite is often associated with the interesting mineral arsenopyrite, with chemical formula FeAsS. In fact the two minerals are really difficult to distinguish from one another. When viewed closely under polarizing microscopes, the two minerals are exhibiting similar crystal forms, colors, streak, luster, and fracture. The only slight difference is that mineral Lollingite is somewhat denser and softer.
Mineral Lollingite was named after its type of locality at Lolling, Huttenburg, Carinthia, Austria. The first specimen of mineral Lollingite was discovered in 1845 at its type of locality at Lolling district.
Mineral Lollingite is most commonly found silver white to gray in color and it is often wonderfully exhibited under petrographic polarizing light microscope. This typical color of mineral Lollingite may also possibly tarnish to a darker color after prolonged exposure to air. The luster that is most commonly exhibited by the mineral in reflected light of the geological polarizing light microscopes is usually metallic. Mineral Lollingite is most often found having indistinct basal cleavage when it is evaluated with the aid of geological polarizing light microscope. The fracture found is often uneven and it is more clearly exhibited under polarizing light microscopes for geologists. The hardness measure of the mineral when it is examined more closely using the Mohs scale method is usually found ranging from 5 to 5.5. When specimen of mineral Lollingite is rubbed on a white porcelain streak plate, it is commonly found leaving gray black streak. The specific gravity measure of the mineral Lollingite usually gives an approximate value ranging from 7.1 grams per cubic centimeters to 7.5 grams per cubic centimeters, which is considered well above average for metallic minerals.
Mineral Lollingite is known to crystallize in the orthorhombic system, which can be seen clearly with the aid of geological microscopes. This crystal system comprises crystals having three mutually perpendicular axes, of which all are of different lengths. Most crystals of mineral Lollingite are found opaque in appearance. The crystal habit of the mineral species usually include prismatic to stubby crystals with a chisel-like domal termination that is usually seen clearly exhibited when the specimen is viewed under polarizing light microscopes. The cross section of the crystals is commonly found diamond-shaped with rounded oblique angles that are clearly seen when evaluated with the aid of petrographic polarizing light microscopes. When viewed closely under polarizing light microscopes, the elongated wedge shaped crystals are seen when the domal termination becomes dominant. Mineral Lollingite can be also found massive in form, compact and also disseminated in veins fillings. There can be also some twins that can be found as star-shaped trillings when the specimen is viewed under polarized light microscopes.
Lollingite is strongly anisotropic. This means that the mineral specimen of Lollingite consequently appears alternately dark and illuminated when viewed between crossed polars of geological polarizing microscopes. Mineral Lollingite tends to be magnetic after heating. The crystals of mineral Lollingite are commonly found striated lengthwise and it is most especially clearly exhibited when viewed under petrographic polarizing light microscopes. Lollingite crystals are non-fluorescent in ultra violet light. Mineral Lollingite is most commonly found associated with their interesting mineral including pyrrhotite, siderite, arsenopyrite, calcite, biotite, calcite, chalcopyrite, vesuvianite, analcime, and sodalite. Mineral Lollingite is a non-radioactive mineral species. There is no specific data found on the toxicity and health dangers for mineral Lollingite. However, the specimens of the mineral should be treated with great care and use of sensible precaution is advised upon handling them.
Mineral Lollingite can be found in mesothermal deposits that are associated with other sulfides and calcite gangue. It can be also found in pegmatites. The best field indicators of mineral Lollingite usually include color, association, streak, hardness, density, crystal habit, and striations. Mineral Lollingite notably occurs at several localities including Lolling, Huttenburg, Carinthia, Austria as well as the Harz in Germany, Cobalt in Connecticut, Franklin in New Jersey, Alexander Co. in North Carolina, Gunnison Co. in Colorado and also Arizona in USA. It can be also found in Ontario, Canada and some other areas like Norway, Sweden, Finland, Brazil, Poland, and the Czech Republic.