The chemical formula of mineral Laurionite is indicated by PbClOH or Lead Chloride Hydroxide. Laurionite is actually a Halide mineral. Mineral Laurionite was first discovered in 1887 at Lavrion District slag localities in Greece. The mineral species was actually named after its type of locality at Laurion, Greece. Laurionite is known to crystallize in the orthorhombic system of crystal formation. In optical mineralogy, this orthorhombic crystal system comprises crystals having three mutually perpendicular axes, of which all are of different lengths.
Laurionite is most commonly used as mineral specimen and it is often found exhibiting wonderful images under polarizing light microscopes used in optical mineralogy. Mineral Laurionite is also considered as a very minor ore of lead and it is usually found exhibiting wonderful appearance when viewed with the aid of an ore polarizing light microscope. Laurionite is actually a rare Halide. It is usually polymorphous with mineral paralaurionite. The two or more minerals are said to be polymorphous if they share the same and exact chemistry but are exhibiting different crystal structure. If only two minerals are involved, the term used is usually dimorphous. In this case, mineral Laurionite has orthorhombic symmetry while paralaurionite has monoclinic symmetry.
Laurionite is usually found forming small colorless vitreous to adamantine crystals that are often clearly visible when viewed with the aid of petrographic polarizing microscope used in optical mineralogy. These crystals are often found showing distinctive V-shaped striations on the prism faces that can be noticed more clearly when the specimen is evaluated with the aid of polarized microscopes for mineralogists. When Laurionite crystals are usually found having prismatic to acicular crystals that are commonly found brittle when viewed under petrographic polarizing light microscopes. Mineral paralaurionite on the other hand forms minute tabular colorless, white or pale yellow crystals that are splendidly exhibited under polarized light microscopes. Mineral Laurionite crystals are found without striations and they are usually not brittle, also flexible but really inelastic.
Laurionite is most commonly found showing colorless to white crystals that are much more splendidly exhibited when viewed under petrographic polarizing light microscopes. Laurionite is most commonly found exhibiting vitreous to adamantine luster in reflected light of petrographic polarizing light microscopes for mineralogists. Laurionite are usually found showing indiscernible cleavage in one direction when viewed under polarizing microscopes for mineralogists. Laurionite is usually found exhibiting uneven fracture under petrographic polarizing microscope used in optical mineralogy. The specific gravity measure of the mineral Laurionite usually gives an approximate value ranging from 6.1 grams per cubic centimeters to 6.2+ grams per cubic centimeters, which is considered very heavy for translucent minerals. The hardness measure of the mineral Laurionite when it is evaluated using the Mohs scale method is usually ranging from 3 to 3.5. Laurionite is most commonly found leaving a white streak when the specimen sample is rubbed on a white porcelain streak plate.
Most Laurionite crystals are found transparent to translucent in appearance. The crystal habit of Laurionite as described in optical mineralogy usually include striated crystals that are often found prismatic to acicular in form with sharply pointed terminations that can be seen clearly when evaluated with the aid of polarizing light microscope. Laurionite also exhibits a very high surface relief when evaluated under several adjustments on the aperture diaphragm of the geological polarizing light microscopes. Laurionite is most commonly found showing biaxial negative figure when is viewed between crossed nicols of petrographic polarizing microscope. The refractive index of the mineral Laurionite is usually found ranging from 2.077 to 2.158. The maximum birefringence of Laurionite is usually 0.081. A strong dispersion can be also found exhibited when the mineral is examined under polarized microscope. Mineral Laurionite is usually found having striations with distinctive V-shapes on the prism faces when viewed under petrographic polarizing light microscopes. The crystals of mineral Laurionite are usually found brittle and this is actually very unlikely to that of mineral paralaurionite, its polymorph. Mineral Laurionite is slightly soluble in cold water, more soluble in warm water. It can be also found soluble in nitric acid. There is no specific data found on the toxicity and health dangers for mineral Laurionite. However, the specimens of the mineral should be treated with great care and use of sensible precaution is advised upon handling them. Laurionite is a non-radioactive mineral species.
Mineral Laurionite is commonly found associated with other interesting minerals like paralaurionite, matlockite, penfieldite, fiedlerite, phosgenite, and cerussite. The best field indicators of the mineral Laurionite usually include associations, localities, striations, crystal habit, and brittleness. Mineral Laurionite is actually a secondary mineral from smelting activities. Mineral Laurionite can be formed in saline water acting on lead slags. It can be also found in oxidation zone in lead deposits. Mineral Laurionite has limited occurrence at very few localities including Laurion, Greece and the Wheal Rose in Cornwall, England.
