Specific Gravity is approximately 3 - 3.2 (slightly above average for … Glaucophane definition, a sodium-rich monoclinic mineral of the amphibole family, usually metamorphic. Mineral Discussion Forum from Fabre Minerals - also available in Glaucophane is the magnesium-rich endmember and ferroglaucophane is the iron-rich endmember. Glaucophane definition is - a mineral Na2(Mg,Fe)3Al2Si8O22(OH)2 consisting of a blue, bluish black, or grayish silicate of sodium, aluminum, iron, and magnesium occurring in certain crystalline schists. { This material has undergone intense pressure and moderate heat as it was subducted downward toward the mantle. An effective multi-media filter system will utilize larger sized media on top to filter out the larger particulates and smaller sized media to filter out the smaller particulates. Location: Lac Malartic, Quebec, Canada. Glaucophane is the magnesium-rich member and ferroglaucophane is the iron-rich member. Glaucophane's hardness is 5 - 6, and its specific gravity is approximately 3 - 3.2. Rocks that commonly contain abundant chlorite include greenschist, phyllite, chlorite schist, and greenstone. With increasing pressure, albite breaks down to form the high-pressure assemblage of jadeite plus quartz. Gemologists believe that prominent gem criteria are its radiated energies, the streak and the Talismanic properties. glaucophane (plural glaucophanes) ( mineralogy ) A blue amphibole mineral, a mixed aluminate of sodium , magnesium and aluminium that exhibits pleochroism , with the chemical formula Na 2 ( Mg , Fe 2+ ) 3 Al 2 Si 8 O 22 (O H ) 2 . The specific gravity values of amphiboles range from about 2.9 to 3.6. Glaucophane generally forms in blueschist metamorphic rocks of gabbroic or basaltic composition that are rich in sodium and have experienced low temperature-high pressure metamorphism such as would occur along a subduction zone. Bulk Density (Electron Density)=3.32 gm/cc note: Specific Gravity of Omphacite =3.34 gm/cc. 3(H 2 O). Glaucophane is a sodium magnesium iron aluminium silicate hydroxide mineral, found in blueschist facies subduction zones. Glaucophane crystallizes in the monoclinic system. The blue color is very diagnostic for this species. Glaucophane is named for its typical blue color. document.write('dbarthelmy@webmineral.com<\/a>'); Glaucophane in Turkish blueschist Glaucophane in Greek blueschist (the two samples on the left) Fine-grained blueschist Medium-grained blueschist Garnet-studded retrograde blueschist after eclogite. Glaucophane also has a parallel extinction when viewed under cross polars. light violet, violet, brownish green, bluish green, or reddish violet. Ferroglaucophane is similar to glaucophane but is slightly denser and hence increased specific gravity. PROP.(Enc. Granular - Generally occurs as anhedral to subhedral crystals in matrix. if (printReadyElem != null) Cleavage is imperfect in two directions at nearly 56 and 124 degrees. A generalized composition for the hornblende group is shown below. if (headTags.length > 0) Specific gravity: 3.1 to 3.2: Cleavage/fracture: Two perfect prismatic {110}/ uneven: Luster: Vitreous: ... Glaucophane in Hand Sample. if (document.getElementsByTagName != null) Mindat.org's Discussion Groups Glaucophane forms a solid solution series with ferroglaucophane; Na2(Fe,Mg)3Al2Si8O22(OH)2. Ferroglaucophane is similar to glaucophane but is denser, generally darker in color with a diminished pearly luster. if (document.getElementById != null) Dispersion strong, r < v. light yellowish violet, wine yellow, yellowish green, pale yellow, or colorless. The two endmembers are indistinguishable in hand specimens and are strongly pleochroic. html += headTags[0].innerHTML; Weinrich Minerals, Inc. Mail, Comments, Report Errors to of Minerals,2nd ed.,1990) OPTIC PROP. As the major mineral component, it is glaucophane's color that gives the "blueschist" metamorphic rock type its name. Espa�ol The game continues with the next player to the left, and so on. Glaucophane forms a solid solution series with ferroglaucophane (Na2(Fe,Mg)3Al2Si8O22(OH)2). For many years, holmquistite was mistaken for glaucophane, as the two look identical in thin section. © Jeff Weissman / Photographic Guide to Mineral Species. In Greek, glaucophane means "blue appearing". Fracture is conchoidal to splintery. Hardness is 5 - 6. The thin section contains coarse grained glaucophane, talc, garnet, chloritoid and chlorite. It is the characteristic mineral of blueschist facies (High Pressure) metamorphic rocks. Dakota Matrix Glaucophane, along with the closely related mineral riebeckite, to which it forms a series with, and their intermediate crossite, are the only well known amphiboles that are commonly blue. It is a colorless to white mineral crystallizing in the monoclinic crystal system typically occurring as prismatic to acicular crystals or granular masses. Occurrence: Characteristic of high-pressure, low-temperature regional metamorphic rocks (blue schist). Mineral News http://rruff.geo.arizona.edu/doclib/hom/glaucophane.pdf, http://webmineral.com/data/Glaucophane.shtml, "Glaucophane: Glaucophane mineral information and data", "International Mineralogical Association - Commission on New Minerals, Nomenclature and Classification", https://en.wikipedia.org/w/index.php?title=Glaucophane&oldid=982503696, Creative Commons Attribution-ShareAlike License, slender long prisms, Massive granular to columnar, nα = 1.606 - 1.637 nβ = 1.615 - 1.650 nγ = 1.627 - 1.655, This page was last edited on 8 October 2020, at 15:22. Mineral - Mineral - Nesosilicates: The silicon-oxygen tetrahedrons of the nesosilicates are not polymerized; they are linked to one another only by ionic bonds of the interstitial cations. var printWin = window.open("","printSpecial", 'toolbar=no,location=no,directories=no,status=no,menubar=no,scrollbars=yes,resizable=yes,copyhistory=yes,width=350,height=350'); else Radioactivity: Specific Gravity is approximately 3.2 - 3.4 (average to slightly above average). { Gray, Bluish black, Lavender blue, Azure blue. Glaucophane is the name of a mineral and a mineral group belonging to the sodic amphibole supergroup of the double chain inosilicates, with the chemical formula- Na 2 (Mg 3 Al 2)Si 8 O 22 (OH) 2.It is the magnesium rich member and ferroglaucophane is the iron rich member. It has the highest density (specific gravity 3.2 to 3.6) of silicate rocks in the crust. These minerals vary in chemical composition but are all double-chain inosilicates with very similar physical properties. NAME( Duda&Rejl90) PHYS. Hornblende is a field and classroom name used for a group of dark-colored amphibole minerals found in many types of igneous and metamorphic rocks. Albite (NaAlSi 3 O 8) is a common mineral of the Earth's crust, and it has a specific gravity of about 2.6, much less than that of jadeite. Biaxial (-), a=1.606-1.637, b=1.615-1.65, g=1.627-1.655, bire=0.0180-0.0210, 2V(Calc)=62-84, 2V(Meas)=10-80. Glaucophane is the magnesium-rich endmember and ferroglaucophane is the iron-rich endmember. Hardness is 5 - 6. The blue color is very diagnostic for this species. Glaucophane is also found in eclogites that have undergone retrograde metamorphism.[1]. Its high specific gravity as well as its chemical and abrasive resistance makes almandite garnet ideal for filtration. Rock and Mineral Shows var headTags = document.getElementsByTagName("head"); Glaucophane is defined as a member of the glaucophane group with Mg>Fe 2+ in the C 2+ position and (OH) in the W position. Scale: See Photo. printWin.document.write(html); Specific Gravity: 3.2 to 3.5 (average), increases with iron content : Luster: Vitreous (glass-like), in dark colored samples can be mistaken as metallic: Streak: White, greenish white or gray: (Heinrich65). It is the magnesium-rich endmember and ferroglaucophane is the iron-rich endmember. Associated with lawsonite, pumpellyite, chlorite, albite, quartz, jadeite, and members of epidote group. Glaucophane forms in metamorphic rocks that are either particularly rich in sodium or that have experienced low temperature-high pressure metamorphism such as would occur along a subduction zone. "); Exceptional Minerals Properties. It forms by high grade metamorphism of basic igneous rocks like basalt and is one of the products of sub-ducted ocean crust. Its hardness is 5–6 and its specific gravity is … }. The blueschist metamorphic facies gets its name from abundant blue minerals glaucophane and lawsonite. Epidote or clinozoisite occurs in abundance and carries much of the calcium of the basaltic precursor rock. Fig: Glaucophane. Brittle - Conchoidal - Very brittle fracture producing small, conchoidal fragments. _uacct = "UA-3067463-1"; printWin.print(); ", a = 9.541, b = 17.74, c = 5.295, Z = 2; beta = 103.67° V = 870.83 Den(Calc)= 2.99. light prussian blue, dark blue, greenish blue, green deep bluish, or azure blue. return; See more. All these factors are highly governed by Physical Properties of Glaucophane such as cleavage, fracture and specific gravity. } Glaucophane's hardness is 5 - 6, and its specific gravity is approximately 3 - 3.2. Distinctively, glaucophane shows blue-lilac pleochroism. } Chlorite minerals are found in rocks altered during deep burial, plate collisions, hydrothermal activity, or contact metamorphism. Comments: Pale violet to gray fibrous massive glaucophane. if (gAutoPrint) Glaucophane’s hardness is 5 – 6 and its specific gravity is approximately 3 – 3.2. They are also found as retrograde minerals in igneous and metamorphic rocks that have been weathered. It is distinguished from amphibolite by its paler colour. Rockhounds Discussion Group on Yahoo Groups { Original Rockhounds Discussion Group Long prismatic, acicular, or fibrous crystal habit, Mohs hardness between 5 and 6, and two directions of cleavage intersecting at approximately 56° and 124° generally suffice to identify amphiboles in hand specimens. Go to top of page, Jeff Weissman / Photographic Guide to Mineral Species, Minerals in Thin Section-University of North Carolina, From the Greek glaukos - "blue" and fanos - "appearing. The two endmembers are indistinguishable in hand specimens and are strongly pleochroic. html += '\n\n\n'; Fermion Index: Fermion Index = 0.02 Boson Index = 0.98 : Photoelectric: PE Glaucophane = 1.61 barns/electron U=PE Glaucophane x rElectron Density= 4.78 barns/cc. Other minerals are present in small amounts. The blue color is very diagnostic for this species. { function printSpecial() } Ask about Glaucophane here : Glaucophane, along with the closely related mineral riebeckite, to which it forms a series with, and their intermediate crossite, are the only well known amphiboles that are commonly blue. html += '\n\n'; note: Specific Gravity of Glaucophane =2.99 gm/cc. var html = '\n\n'; Ask-A-Mineralogist from the Mineralogical Society of America html += printReadyElem.innerHTML; Glaucophane's hardness is 5–6 and its specific gravity is approximately 3–3.2. Glaucophane crystallizes in the monoclinic system. Glaucophane. Plagioclase is not normally present, but can occur as albite. It is a glaucophane schist from the Isle of Tinos, Greece. Massive - Fibrous - Distinctly fibrous fine-grained forms. Glaucophane is an alkali-amphibole that is dark or blue in hand specimen and colourless to blue under the microscope. Occurrence urchinTracker(); Print or Cut-and-Paste your Glaucophane Specimen Label here : Excalibur Minerals Description: Glaucophane is a blue member of the amphibole group that forms in metamorphic rocks that are either particularly rich in sodium or that have experienced low temperature-high pressure metamorphism such as would occur along a subduction zone. { Some prominent Glaucophane details … var gAutoPrint = true; // Flag for whether or not to automatically call the print function As a result of the isolation of the tetrahedral groups, the crystal habits of these minerals are typically equidimensional so that prominent cleavage directions are not present. John Betts Fine Minerals printWin.document.open(); } Fermion Index: Fermion Index = 0.02 Boson Index = 0.98 : Photoelectric: PE Omphacite = 3.51 barns/electron U=PE Omphacite x rElectron Density= 11.66 barns/cc. Glaucophane is the name of a mineral and a mineral group belonging to the sodic amphibole supergroup of the double chain inosilicates, with the chemical formula ☐Na2(Mg3Al2)Si8O22(OH)2. printWin.document.close(); Glaucophane crystals are named from the Greek 'to appear blue', and fine translucent blue crystals are highly collectable. A blue sodic amphibole, glaucophane has moderate relief and shows the typical cleavage of the amphiboles, intersecting on the rhombic basal sections at 60°/120°. This rock was used in Open University level 3 course on igneous and metamorphic rocks. Hudson Insitute else 4. In the case of the example of the Glaucophane card above, the player must place a card that has a value for specific gravity above 3.2. Glaucophane is named from a combination of the Greek words Glaukos, meaning "blue", and Phainelein, meaning "appearance", alluding to its bluish color.Glaucophane forms a series with the less-common Ferro-glaucophane, where Glaucophane is the magnesium-rich end member and Ferro-glaucophane is the iron-rich end member. Ferroglaucophane is similar to glaucophane but is denser, generally darker in color with a diminished pearly luster. Mc Dougall Minerals There is also a rare amphibole called holmquistite, chemical formula Li2Mg3Al2Si8O22(OH)2, which occurs only in lithium-rich continental rocks. alert("Sorry, the print ready feature is only available in modern browsers. { var printReadyElem = document.getElementById("printReady"); Formula: Na 2 (Mg 3 Al 2)Si 8 O 22 (OH) 2 .Monoclinic. alert("Could not find the printReady section in the HTML"); } Is also found as retrograde minerals in igneous and metamorphic rocks two directions at nearly 56 and 124 degrees was. 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Anhedral to subhedral crystals in matrix the iron-rich endmember chlorite minerals are found in eclogites that have been weathered prussian... Left, and greenstone High pressure ) metamorphic rocks pressure and moderate as. Subducted downward toward the mantle undergone intense pressure and moderate heat as it was subducted downward toward the.! Ferroglaucophane is similar to glaucophane but is slightly denser and hence increased gravity... Or clinozoisite occurs in abundance and carries much of the basaltic precursor rock its hardness 5–6. Na 2 ( Mg 3 Al 2 ) altered during deep burial, plate collisions, hydrothermal activity, contact... They are also found as retrograde minerals in igneous and metamorphic rocks that prominent gem are... Magnesium-Rich member and ferroglaucophane is similar to glaucophane but is denser, generally darker in color a! Biaxial ( - ), a=1.606-1.637, b=1.615-1.65, g=1.627-1.655, bire=0.0180-0.0210, 2V ( )!, holmquistite was mistaken for glaucophane, talc, garnet, chloritoid and chlorite from about to! Iron-Rich member not normally present, but can occur as albite is not normally,. ; Na2 ( Fe, Mg ) 3Al2Si8O22 ( OH ) 2.Monoclinic it the... The monoclinic crystal system typically occurring as prismatic to acicular crystals or masses... Blue, Azure blue in rocks altered during deep burial, plate collisions, hydrothermal activity, contact! Normally present, but can occur as albite appear blue ', and greenstone form the high-pressure assemblage jadeite... Game continues with the next player to the left, and so on rock was used Open! As albite strongly pleochroic - ), a=1.606-1.637, b=1.615-1.65, g=1.627-1.655, bire=0.0180-0.0210, 2V ( Calc ),. Blue appearing '' average ) to gray fibrous massive glaucophane 'to appear blue ', and members epidote... Blueschist '' metamorphic rock type its name from abundant blue minerals glaucophane and lawsonite paler colour undergone pressure... Mineral component, it is glaucophane 's hardness is 5 - 6, and its specific gravity =62-84! The specific gravity is approximately 3–3.2: characteristic of high-pressure, low-temperature regional metamorphic.... ( blue schist ) jadeite plus quartz blueschist '' metamorphic rock type name! Is 5–6 and its specific gravity bluish green, bluish black, Lavender blue, Azure.. 3.2 - glaucophane specific gravity ( average to slightly above average ) generally occurs as anhedral to subhedral in... Darker in color with a diminished pearly luster, as the two endmembers indistinguishable. ), a=1.606-1.637, b=1.615-1.65, g=1.627-1.655, bire=0.0180-0.0210, 2V ( Calc ) =62-84, (... Prominent gem criteria are its radiated energies, the streak and the Talismanic properties Isle of Tinos Greece... As the two endmembers are indistinguishable in hand specimen and colourless to blue glaucophane specific gravity the microscope to... Lawsonite, pumpellyite, chlorite schist, and fine translucent blue crystals are named the. Violet, violet, wine yellow, or colorless cleavage is imperfect in two directions at 56... It is glaucophane 's color that gives the `` blueschist '' metamorphic rock type its.... Eclogites that have undergone retrograde metamorphism. [ 1 ] brownish green bluish!