The chemical formula of the mineral Glaucophane is indicated by Na2(Mg, Fe)3Al2Si8O22(OH)2 or Sodium Magnesium Iron Aluminum Silicate Hydroxide. Glaucophane is actually a Silicate mineral. Glaucophane also belongs to the Amphibole Group of minerals. The name of the mineral species Glaucophane is derived from the Greek words glaukos, which means blue and fanos, which means appearing. Glaucophane in Greek means blue appearing. This is actually an allusion to the typical blue color exhibited by the mineral when evaluated under polarizing microscopes for mineralogists. Mineral Glaucophane is known to crystallize in the monoclinic system of crystal formation. In optical mineralogy, the monoclinic system of crystal formation comprises crystals having three axes of unequal lengths. Two of which are usually found in a position that is oblique or not perpendicular to one another. However, both of which are commonly found perpendicular to the third axis.
Glaucophane is only used as mineral specimen and most commonly found exhibiting nice and interesting appearance when viewed under petrographic polarizing microscopes used in the field of optical mineralogy. Glaucophane is most commonly found colored blue when viewed with the aid of polarized microscope for geologists. And this blue color is very diagnostic for this mineral species. Glaucophane is actually one of the few amphibole minerals that are typically blue in color. It also found forming a solid solution series with ferroglaucophane. Mineral Glaucophane is actually the magnesium rich end member of the series while ferroglaucophane is the iron rich end member. The two minerals are very similar only that ferroglaucophane is denser and generally darker in color with pearly luster when viewed with the aid of polarizing microscopes for geologists.
Mineral Glaucophane is most commonly found blue to dull gray in color and are usually more splendidly exhibited when viewed with the aid of polarizing microscope used in optical mineralogy. Glaucophane is most commonly found exhibiting vitreous to pearly luster when specimen is viewed in reflected light of polarizing microscope for mineralogists. Glaucophane is most commonly found showing imperfect cleavage in two directions at nearly 56 to 124 degrees, which can be seen more fascinatingly wonderful when viewed with the aid of petrographic polarizing light microscope used in optical mineralogy. Glaucophane is most often found showing conchoidal to splintery fracture when specimen is viewed closely under polarizing microscope for geologists. The specific gravity measure of Glaucophane usually gives an approximate value ranging from 3.0 grams per cubic centimeters to 3.2 grams per cubic centimeters, which is considered slightly above average for non-metallic minerals. The hardness measure of mineral Glaucophane when it is evaluated using the Mohs scale method is usually found ranging from 5 to 6. Glaucophane is most commonly found leaving a pale gray to blue streak when the mineral section is rubbed on a white porcelain streak plate.
Generally, Glaucophane crystals are found translucent in appearance. The crystal habit of the mineral Glaucophane as described in the field of optical mineralogy usually includes scarce prismatic to acicular crystals that are commonly found clearly exhibited when the mineral is evaluated with the aid of polarizing light microscopes. Glaucophane mineral can be also found in fibrous form that is usually splendidly exhibited under petrographic polarizing light microscopes. It can be also found granular or massive in form. Glaucophane is commonly found having a biaxial negative figure when mineral is evaluated between crossed nicols of polarizing microscopes used in optical mineralogy. The maximum birefringence display of the mineral section between crossed polars of petrographic polarizing microscope Glaucophane usually found ranging from 0.0180 to 0.0210. Glaucophane also shows strong dispersion in plane light of geological polarizing microscopes. Glaucophane is a non-fluorescent mineral species. Mineral Glaucophane is commonly found pleochroic when viewed in plane-polarized light of geological polarizing microscope. The pleochroic colors found are usually in different shades of blue, violet and green. Glaucophane is a non-radioactive mineral species.
Glaucophane is most commonly found associated with other interesting minerals including pumpellyite, chlorite, actinolite, epidote, jadeite, lawsonite, quartz, omphacite, rutile, garnets, sphene, albite, aragonite, barroisite and cummingtonite. The best field indicators of mineral Glaucophane usually include cleavage, crystal habit, especially the cross section, color, association, luster and environment of formation. Mineral Glaucophane is typically formed in blue schist facies or in highly metamorphic zones. It has been known that these facies are actually formed from material caught under subduction zones kin mountain belt regions. If these materials are subjected to moderate heat and intense pressure when they were subducted downward toward the mantle. The blue color of mineral Glaucophane actually gives the name of the facies. Mineral Glaucophane can be also found in eclogites which were subjected to retrograde metamorphism. Glaucophane notably occurs at types of localities in Italy, Greece, United States, United Kingdom, Japan and Australia.
