[{"data":1,"prerenderedAt":-1},["ShallowReactive",2],{"minerals:one:32185":3},{"id":4,"longid":5,"guid":6,"name":7,"shortcode_ima":8,"entrytype":9,"entrytype_text":10,"varietyof":11,"synid":8,"polytypeof":8,"groupid":12,"weighting":13,"nolocadd":14,"blacklisted":14,"mindat_formula":15,"mindat_formula_note":8,"ima_formula":8,"elements":16,"sigelements":20,"key_elements":8,"impurities":8,"cim":8,"ima_status":8,"ima_notes":8,"ima_history":8,"approval_year":8,"publication_year":8,"discovery_year":8,"strunz10ed1":21,"strunz10ed2":21,"strunz10ed3":21,"strunz10ed4":8,"dana8ed1":8,"dana8ed2":8,"dana8ed3":8,"dana8ed4":8,"csystem":8,"cclass":8,"spacegroup":8,"spacegroupset":21,"a":8,"b":8,"c":8,"alpha":8,"beta":8,"gamma":8,"aerror":8,"berror":8,"cerror":8,"alphaerror":8,"betaerror":8,"gammaerror":8,"va3":8,"z":8,"csmetamict":14,"commentcrystal":8,"twinning":8,"tranglide":8,"parting":8,"epitaxidescription":8,"morphology":8,"tlform":8,"hmin":8,"hmax":8,"hardtype":8,"vhnmin":21,"vhnmax":21,"vhnerror":8,"vhng":8,"vhns":8,"commenthard":8,"dmeas":21,"dmeas2":21,"dcalc":21,"dmeaserror":8,"dcalcerror":8,"commentdense":8,"lustre":8,"lustretype":8,"commentluster":8,"diapheny":8,"streak":8,"colour":8,"commentcolor":8,"colors":8,"streak_colors":8,"luminescence":8,"uv":8,"cleavage":8,"cleavagetype":8,"fracturetype":8,"tenacity":8,"commentbreak":8,"opticaltype":8,"opticalsign":8,"opticalalpha":8,"opticalalpha2":8,"opticalalphaerror":8,"opticalbeta":8,"opticalbeta2":8,"opticalbetaerror":8,"opticalgamma":8,"opticalgamma2":8,"opticalgammaerror":8,"opticalomega":8,"opticalomega2":21,"opticalomegaerror":8,"opticalepsilon":8,"opticalepsilon2":21,"opticalepsilonerror":8,"opticaln":8,"opticaln2":8,"opticalnerror":8,"optical2vcalc":8,"optical2vcalc2":8,"optical2vcalcerror":8,"optical2vmeasured":8,"optical2vmeasured2":8,"optical2vmeasurederror":8,"rimin":8,"rimax":8,"opticaldispersion":8,"opticalpleochroism":8,"opticalpleochorismdesc":8,"opticalbirefringence":8,"opticalcomments":8,"opticalcolour":8,"opticalinternal":8,"opticaltropic":8,"opticalanisotropism":8,"opticalbireflectance":8,"opticalextinction":8,"opticalr":8,"specdispm":8,"ir":8,"electrical":8,"magnetism":8,"thermalbehaviour":8,"other":8,"industrial":8,"occurrence":8,"otheroccurrence":8,"type_specimen_store":8,"description_short":8,"aboutname":22,"rock_parent":8,"rock_parent2":8,"rock_root":23,"rock_bgs_code":8,"meteoritical_code":8,"updttime":24,"reviewed_at":8,"variety_of":25,"varieties":33,"group_members":38,"associates":122,"confused_with":123,"type_localities":124,"occurrence_total":125,"citations":126,"images":168,"structures":213,"synonyms":214,"language_names":215,"wikidata_qid":8,"texts":216},32185,"1:1:32185:7","db9e1576-012c-46f9-bddd-96bcada88a29","Opal-CT",null,2,"variety",3004,10916,894,false,"SiO\u003Csub>2\u003C\u002Fsub>·nH\u003Csub>2\u003C\u002Fsub>O",[17,18,19],"Si","O","H",[17,18,19],"0","C stands for cristobalite and T for tridymite.\r\nThe origin of the word \"opal\" is uncertain. It may be from the Sanskrit \"upala\", meaning \"stone\" or \"precious stone\" or from opalus, the ancient Latin name for the gem (Pliny the Elder, 75-79). Pliny may have also referred to the gem as paederos, but a modern commentary by Kostov (2008) questions if that name was actually applied to the opal in the modern sense.",0,"2025-08-11 12:14:57",{"id":11,"name":26,"entrytype":23,"csystem":8,"ima_formula":27,"mindat_formula":15,"hmin":28,"hmax":29,"dmeas":30,"dcalc":21,"strunz10ed1":31,"primary_image_id":32},"Opal","SiO\u003Csub>2\u003C\u002Fsub> · nH\u003Csub>2\u003C\u002Fsub>O",5.5,6.5,"1.9","4",18161,[34],{"id":35,"name":36,"entrytype":9,"csystem":8,"ima_formula":8,"mindat_formula":15,"hmin":8,"hmax":8,"dmeas":8,"dcalc":8,"primary_image_id":37},5162,"Lussatite",71612,[39,48,57,65,70,78,84,88,93,97,104,109,115],{"id":40,"name":41,"entrytype":23,"csystem":42,"ima_formula":43,"mindat_formula":44,"hmin":29,"hmax":45,"dmeas":8,"dcalc":46,"primary_image_id":47},39335,"Chibaite","Isometric","SiO\u003Csub>2\u003C\u002Fsub> · n(CH\u003Csub>4\u003C\u002Fsub>,C\u003Csub>2\u003C\u002Fsub>H\u003Csub>6\u003C\u002Fsub>,C\u003Csub>3\u003C\u002Fsub>H\u003Csub>8\u003C\u002Fsub>,C\u003Csub>4\u003C\u002Fsub>H\u003Csub>10\u003C\u002Fsub>) (n\u003Csub>max\u003C\u002Fsub> = 3\u002F17)","SiO\u003Csub>2\u003C\u002Fsub>·n(CH\u003Csub>4\u003C\u002Fsub>, C\u003Csub>2\u003C\u002Fsub>H\u003Csub>6\u003C\u002Fsub>, C\u003Csub>3\u003C\u002Fsub>H\u003Csub>8\u003C\u002Fsub>, i-C\u003Csub>4\u003C\u002Fsub>H\u003Csub>10\u003C\u002Fsub>) (n = 3\u002F17 (max))",7,"1.933",5390,{"id":49,"name":50,"entrytype":23,"csystem":51,"ima_formula":52,"mindat_formula":52,"hmin":53,"hmax":54,"dmeas":21,"dcalc":55,"primary_image_id":56},1104,"Coesite","Monoclinic","SiO\u003Csub>2\u003C\u002Fsub>",7.5,8,"2.92",6030,{"id":58,"name":59,"entrytype":23,"csystem":60,"ima_formula":52,"mindat_formula":52,"hmin":61,"hmax":45,"dmeas":62,"dcalc":63,"primary_image_id":64},1155,"Cristobalite","Tetragonal",6,"2.32","2.33",6449,{"id":66,"name":67,"entrytype":23,"csystem":68,"ima_formula":52,"mindat_formula":52,"hmin":29,"hmax":29,"dmeas":21,"dcalc":21,"primary_image_id":69},2363,"Lechatelierite","Amorphous",14243,{"id":71,"name":72,"entrytype":23,"csystem":60,"ima_formula":73,"mindat_formula":74,"hmin":29,"hmax":45,"dmeas":75,"dcalc":76,"primary_image_id":77},2630,"Melanophlogite","C\u003Csub>2\u003C\u002Fsub>H\u003Csub>17\u003C\u002Fsub>O\u003Csub>5\u003C\u002Fsub> · Si\u003Csub>46\u003C\u002Fsub>O\u003Csub>92\u003C\u002Fsub>","46SiO\u003Csub>2\u003C\u002Fsub>·6(N\u003Csub>2\u003C\u002Fsub>,CO\u003Csub>2\u003C\u002Fsub>)·2(CH\u003Csub>4\u003C\u002Fsub>,N\u003Csub>2\u003C\u002Fsub>)","1.99","1.98",15779,{"id":79,"name":80,"entrytype":23,"csystem":51,"ima_formula":27,"mindat_formula":52,"hmin":61,"hmax":61,"dmeas":81,"dcalc":82,"primary_image_id":83},2739,"Mogánite","2.52","2.55",16422,{"id":85,"name":86,"entrytype":9,"csystem":8,"ima_formula":8,"mindat_formula":15,"hmin":8,"hmax":8,"dmeas":21,"dcalc":21,"primary_image_id":87},32187,"Opal-AG",71563,{"id":89,"name":90,"entrytype":9,"csystem":8,"ima_formula":8,"mindat_formula":15,"hmin":28,"hmax":29,"dmeas":91,"dcalc":21,"primary_image_id":92},1959,"Opal-AN","2.0",59857,{"id":94,"name":95,"entrytype":9,"csystem":8,"ima_formula":8,"mindat_formula":15,"hmin":8,"hmax":8,"dmeas":21,"dcalc":21,"primary_image_id":96},32186,"Opal-C",71596,{"id":98,"name":99,"entrytype":23,"csystem":100,"ima_formula":52,"mindat_formula":52,"hmin":45,"hmax":45,"dmeas":101,"dcalc":102,"primary_image_id":103},3337,"Quartz","Trigonal","2.65","2.66",30579,{"id":105,"name":106,"entrytype":23,"csystem":107,"ima_formula":52,"mindat_formula":52,"hmin":8,"hmax":8,"dmeas":21,"dcalc":108,"primary_image_id":8},26715,"Seifertite","Orthorhombic","4.294",{"id":110,"name":111,"entrytype":23,"csystem":60,"ima_formula":52,"mindat_formula":52,"hmin":53,"hmax":54,"dmeas":112,"dcalc":113,"primary_image_id":114},3790,"Stishovite","4.35","4.29",22954,{"id":116,"name":117,"entrytype":23,"csystem":118,"ima_formula":52,"mindat_formula":52,"hmin":29,"hmax":45,"dmeas":119,"dcalc":120,"primary_image_id":121},4015,"Tridymite","Triclinic","2.25","2.28",24496,[],[],[],77,[127,132,136,140,144,148,153,158,163],{"id":128,"year":129,"html":130,"doi":131},565312,1971,"Jones, J. B., Segnit, E. R. (1971) The nature of opal I. nomenclature and constituent phases. \u003Ci>Journal of the Geological Society of Australia\u003C\u002Fi>,  18 (1) 57-68 \u003Ca target='_blank' href='https:\u002F\u002Fdoi.org\u002F10.1080\u002F00167617108728743'>doi:10.1080\u002F00167617108728743\u003C\u002Fa>","10.1080\u002F00167617108728743",{"id":133,"year":134,"html":135,"doi":8},16121337,1994,"Graetsch, H. (1994) Structural characteristics of opaline and microcrystalline silica minerals. in: Heaney, P.J., Gibbs, G.V., editors. Reviews in Mineralogy Volume 29 Silica - Physical behaviour, geochemistry and materials applications. Mineralogical Society of America, 209-232.",{"id":137,"year":134,"html":138,"doi":139},3235954,"Elzea, J.M., Odom, I.E., Miles, W.J. (1994) Distinguishing well ordered opal-CT and opal-C from high temperature cristobalite by x-ray diffraction. \u003Ci>Analytica Chimica Acta\u003C\u002Fi>, 286 (1). 107-116 \u003Ca target='_blank' href='https:\u002F\u002Fdoi.org\u002F10.1016\u002F0003-2670(94)80182-7'>doi:10.1016\u002F0003-2670(94)80182-7\u003C\u002Fa>","10.1016\u002F0003-2670(94)80182-7",{"id":141,"year":142,"html":143,"doi":8},16119011,2008,"Kostov, Rusian I. (2008) Orphic Lithica As A Source Of Late Antiquity Mineralogical Knowledge. \u003Ci>Annual Of The University Of Mining And Geology “ST. Ivan Rilski”\u003C\u002Fi>,  51 (1) 109-115",{"id":145,"year":142,"html":146,"doi":147},1104439,"Day, R., Jones, B. (2008) Variations in Water Content in Opal-A and Opal-CT from Geyser Discharge Aprons. \u003Ci>Journal of Sedimentary Research\u003C\u002Fi>,  78 (4) 301-315 \u003Ca target='_blank' href='https:\u002F\u002Fdoi.org\u002F10.2110\u002Fjsr.2008.030'>doi:10.2110\u002Fjsr.2008.030\u003C\u002Fa>","10.2110\u002Fjsr.2008.030",{"id":149,"year":150,"html":151,"doi":152},650161,2014,"Wilson, M.J. (2014) The structure of opal-CT revisited. \u003Ci>Journal of Non-Crystalline Solids\u003C\u002Fi>,  405. 68-75 \u003Ca target='_blank' href='https:\u002F\u002Fdoi.org\u002F10.1016\u002Fj.jnoncrysol.2014.08.052'>doi:10.1016\u002Fj.jnoncrysol.2014.08.052\u003C\u002Fa>","10.1016\u002Fj.jnoncrysol.2014.08.052",{"id":154,"year":155,"html":156,"doi":157},7735973,2019,"Curtis, Neville J., Gascooke, Jason R., Johnston, Martin R., Pring, Allan (2019) A Review of the Classification of Opal with Reference to Recent New Localities. \u003Ci>Minerals\u003C\u002Fi>,  9 (5) 299 \u003Ca target='_blank' href='https:\u002F\u002Fdoi.org\u002F10.3390\u002Fmin9050299'>doi:10.3390\u002Fmin9050299\u003C\u002Fa>","10.3390\u002Fmin9050299",{"id":159,"year":160,"html":161,"doi":162},653299,2020,"Fröhlich, François (2020) The opal-CT nanostructure. \u003Ci>Journal of Non-Crystalline Solids\u003C\u002Fi>,  533. 119938 \u003Ca target='_blank' href='https:\u002F\u002Fdoi.org\u002F10.1016\u002Fj.jnoncrysol.2020.119938'>doi:10.1016\u002Fj.jnoncrysol.2020.119938\u003C\u002Fa>","10.1016\u002Fj.jnoncrysol.2020.119938",{"id":164,"year":165,"html":166,"doi":167},18364145,2025,"Lee, Seungyeol; Xu, Huifang; Xu, Hongwu; Xu, Wenqian (2025) Reexamination of the structure of nanomineral opal-CT using synchrotron X-ray diffraction, transmission electron microscopy, X-ray scattering structure factor, and pair distribution function analyses. \u003Ci>American Mineralogist\u003C\u002Fi>,  110 (5).  \u003Ca target='_blank' href='https:\u002F\u002Fdoi.org\u002F10.2138\u002Fam-2024-9333'>doi:10.2138\u002Fam-2024-9333\u003C\u002Fa>","10.2138\u002Fam-2024-9333",[169,179,189,199,206],{"id":170,"source_url":171,"license_code":172,"credit_html":173,"title":174,"description":175,"author":176,"original_width":177,"original_height":178},71613,"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=7562562","CC BY-SA 4.0","Didier Descouens, via \u003Ca href=\"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=7562562\" rel=\"noopener\">Wikimedia Commons\u003C\u002Fa>","LussatiteUV.jpg","\u003Ca href=\"https:\u002F\u002Fen.wikipedia.org\u002Fwiki\u002FOpal\" class=\"extiw\" title=\"en:Opal\">Opal-CT\u003C\u002Fa> \n\u003Cdl>\u003Cdd>\u003Cdl>\u003Cdd>Size : View (7x7cm)\u003C\u002Fdd>\n\u003Cdd>Locality : Mine des Rois, Dallet, Pont-du-Château, Puy-de-Dôme, Auvergne, France -  A:Daylight B:Ultraviolet light\u003C\u002Fdd>\u003C\u002Fdl>\u003C\u002Fdd>\u003C\u002Fdl>","Didier Descouens",5876,2835,{"id":180,"source_url":181,"license_code":182,"credit_html":183,"title":184,"description":185,"author":186,"original_width":187,"original_height":188},65251,"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=87652802","CC BY 4.0","Marie-Lan Taÿ Pamart, via \u003Ca href=\"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=87652802\" rel=\"noopener\">Wikimedia Commons\u003C\u002Fa>","Opal-CT Lussat MNHN Minéralogie.jpg","Opal-CT on bituminous limestone from Lussat, France. Gallery of Mineralogy and Geology of the French National Museum of Natural History in Paris.","Marie-Lan Taÿ Pamart",5000,3750,{"id":190,"source_url":191,"license_code":192,"credit_html":193,"title":194,"description":195,"author":196,"original_width":197,"original_height":198},37666,"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=153198571","CC BY 2.0","James St. John, via \u003Ca href=\"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=153198571\" rel=\"noopener\">Wikimedia Commons\u003C\u002Fa>","Precious opal (Tertiary; Ethiopia) 5.jpg","Precious opal from the Tertiary of Ethiopia.\n\u003Cp>A mineral is a naturally-occurring, solid, inorganic, crystalline substance having a fairly definite chemical composition and having fairly definite physical properties.  At its simplest, a mineral is a naturally-occurring solid chemical.  Currently, there are over 6000 named and described minerals - about 200 of them are common and about 20 of them are very common.  Mineral classification is based on anion chemistry.  Major categories of minerals are: elements, sulfides, oxides, halides, carbonates, sulfates, phosphates, and silicates.\n\u003C\u002Fp>\u003Cp>The silicates are the most abundant and chemically complex group of minerals.  All silicates have silica as the basis for their chemistry.  \"Silica\" refers to SiO2 chemistry.  The fundamental molecular unit of silica is one small silicon atom surrounded by four large oxygen atoms in the shape of a triangular pyramid - this is the silica tetrahedron - SiO4.  Each oxygen atom is shared by two silicon atoms, so only half of the four oxygens \"belong\" to each silicon.  The resulting formula for silica is thus SiO2, not SiO4.\n\u003C\u002Fp>\u003Cp>Opal is hydrous silica (SiO2·nH2O).  Technically, opal is not a mineral because it lacks a crystalline structure.  Opal is supposed to be called a mineraloid.  Opal is made up of extremely tiny spheres (colloids) that can be seen with a scanning electron microscope (SEM).\n\u003C\u002Fp>\u003Cp>Gem-quality opal, or precious opal, has a wonderful rainbow play of colors (opalescence).  This play of color is the result of light being diffracted by planes of voids between large areas of regularly packed, same-sized opal colloids.  Different opalescent colors are produced by colloids of differing sizes.  If individual colloids are larger than 140 x 10-6 mm in size, purple & blue & green colors are produced.  Once colloids get as large as about 240 x 10-6 mm, red color is seen (Carr et al., 1979).\n\u003C\u002Fp>\u003Cp>Not all opals have the famous play of colors, however.  Common opal has a wax-like luster & is often milky whitish with no visible color play at all.  Opal is moderately hard (H = 5 to 6), has a white streak, and has conchoidal fracture.\n\u003C\u002Fp>\u003Cp>Several groups of organisms make skeletons of opaline silica, for example hexactinellid sponges, diatoms, radiolarians, silicoflagellates, and ebridians.  Some organisms incorporate opal into their tissues, for example horsetails\u002Fscouring rushes and sawgrass.  Sometimes, fossils are preserved in opal or precious opal.\n\u003C\u002Fp>\u003Cp>The specimen seen here is opal-CT, which consists of extremely tiny cristobalite-tridymite aggregates called leptospheres.  This is in contrast to Australian precious opal, which is opal-A (= consists of amorphous, hydrous silica colloids).  Ethiopian precious opal occurs as nodules in Tertiary-aged volcanic tuffs.\n\u003C\u002Fp>\n\u003Chr>\n\u003Cp>Photo gallery of opal:\nwww.mindat.org\u002Fgallery.php?min=3004\n\u003C\u002Fp>\n\u003Chr>\n\u003Cp>Reference cited:\n\u003C\u002Fp>\nCarr et al. (1979) - Andamooka opal fields: the geology of the precious stones field and the results of the subsidised mining program.  Geological Survey of South Australia Department of Mines and Energy Report of Investigations 51.  68 pp.","James St. John",4000,2526,{"id":200,"source_url":201,"license_code":192,"credit_html":202,"title":203,"description":195,"author":196,"original_width":204,"original_height":205},9755,"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=153198580","James St. John, via \u003Ca href=\"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=153198580\" rel=\"noopener\">Wikimedia Commons\u003C\u002Fa>","Precious opal (Tertiary; Ethiopia) 10.jpg",1687,1136,{"id":207,"source_url":208,"license_code":192,"credit_html":209,"title":210,"description":195,"author":196,"original_width":211,"original_height":212},37671,"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=153198589","James St. John, via \u003Ca href=\"https:\u002F\u002Fcommons.wikimedia.org\u002F?curid=153198589\" rel=\"noopener\">Wikimedia Commons\u003C\u002Fa>","Precious opal (Tertiary; Ethiopia) 13.jpg",1642,1202,[],[],[],{"history":8,"applications":8}]