[{"data":1,"prerenderedAt":-1},["ShallowReactive",2],{"detail-sidebar-cat-0-en-105":3,"doc-seo-657903-105":59,"doc-detail-657903-en":130},{"code":4,"msg":5,"data":6},0,"success",[7,13,18,23,28,33,38,43,48,51,55],{"id":8,"doc_module":4,"doc_module_name":9,"category_name":10,"show_sort_weight":11,"slug":12},1,"Document","Story & Novel",90,"story-novel",{"id":14,"doc_module":4,"doc_module_name":9,"category_name":15,"show_sort_weight":16,"slug":17},2,"Literature",80,"literature",{"id":19,"doc_module":4,"doc_module_name":9,"category_name":20,"show_sort_weight":21,"slug":22},4,"Exam",70,"exam",{"id":24,"doc_module":4,"doc_module_name":9,"category_name":25,"show_sort_weight":26,"slug":27},5,"Comic",60,"comic",{"id":29,"doc_module":4,"doc_module_name":9,"category_name":30,"show_sort_weight":31,"slug":32},6,"Technology",50,"technology",{"id":34,"doc_module":4,"doc_module_name":9,"category_name":35,"show_sort_weight":36,"slug":37},7,"Healthcare",40,"healthcare",{"id":39,"doc_module":4,"doc_module_name":9,"category_name":40,"show_sort_weight":41,"slug":42},8,"Research & Report",30,"research-report",{"id":44,"doc_module":4,"doc_module_name":9,"category_name":45,"show_sort_weight":46,"slug":47},9,"Religion & Spirituality",20,"religion-spirituality",{"id":46,"doc_module":4,"doc_module_name":9,"category_name":49,"show_sort_weight":46,"slug":50},"World Cup","world-cup",{"id":52,"doc_module":4,"doc_module_name":9,"category_name":53,"show_sort_weight":52,"slug":54},10,"Lifestyle","lifestyle",{"id":56,"doc_module":4,"doc_module_name":9,"category_name":57,"show_sort_weight":24,"slug":58},19,"General","general",{"code":4,"msg":60,"data":61},"ok",{"site_id":62,"language":63,"slug":64,"title":65,"keywords":66,"description":67,"schema_data":68,"social_meta":123,"head_meta":125,"extra_data":127,"updated_unix":129},105,"en","fire-opal-bill-attwell-1-terminology","Fire Opal - Bill Attwell - 1) Terminology","","Fire opal is explained through its terminology and optical behavior. The document distinguishes fire and play of colour: “fire” is defined as the dispersion-caused display of multicolours on the gem’s surface, while play of colour is internal, produced by diffraction. It further discusses how light separates into component colours and why many fire opals lack the traditional expectations of fire or play of colour. Practical guidance follows on cutting orientation, common naming misconceptions, and gemstone setup considerations.",{"@graph":69,"@context":122},[70,84,105],{"@type":71,"itemListElement":72},"BreadcrumbList",[73,77,79,82],{"item":74,"name":75,"@type":76,"position":8},"https://docshare.wps.com","Home","ListItem",{"item":78,"name":9,"@type":76,"position":14},"https://docshare.wps.com/document/",{"item":80,"name":30,"@type":76,"position":81},"https://docshare.wps.com/document/technology/",3,{"item":83,"name":65,"@type":76,"position":19},"https://docshare.wps.com/document/fire-opal-bill-attwell-1-terminology/657903/",{"url":83,"name":65,"@type":85,"image":86,"author":91,"headline":65,"publisher":94,"fileFormat":97,"inLanguage":63,"description":67,"dateModified":98,"datePublished":99,"encodingFormat":97,"isAccessibleForFree":100,"interactionStatistic":101},"DigitalDocument",{"url":87,"@type":88,"width":89,"height":90},"https://docshare.wps.com/thumbnails/fire-opal-bill-attwell-1-terminology/657903.png","ImageObject",300,407,{"name":92,"@type":93},"Mabel","Person",{"url":74,"name":95,"@type":96},"DocShare","Organization","application/pdf","2026-10-29","2026-10-26",true,{"@type":102,"interactionType":103,"userInteractionCount":29},"InteractionCounter",{"@type":104},"ViewAction",{"@type":106,"mainEntity":107},"FAQPage",[108,114,118],{"name":109,"@type":110,"acceptedAnswer":111},"What does “fire” mean in fire opal, and how is it different from play of colour?","Question",{"text":112,"@type":113},"In fire opal, “fire” refers to multicolours displayed on the gem’s surface due to dispersion. Play of colour refers to multicolours seen inside the opal, caused by diffraction.","Answer",{"name":115,"@type":110,"acceptedAnswer":116},"Why do faceters need to orient the stone table parallel to the plane of diffraction?",{"text":117,"@type":113},"The orientation helps reflected but separated light rays return through the table, improving the desired optical outcome when cutting the facets.",{"name":119,"@type":110,"acceptedAnswer":120},"How should hardness and brittleness concerns affect faceting and jewelry settings?",{"text":121,"@type":113},"Hardness (about 5.5–6 Mohs) requires careful cutting to avoid overcutting facets, especially smaller ones. Brittleness can be managed with gentle technique (e.g., grit choice and slow/moderate speeds) and by choosing settings that better protect the stone, such as considering bezels over rings.","https://schema.org",{"og:url":83,"og:type":124,"og:title":65,"og:site_name":95,"og:description":67},"article",{"robots":126,"canonical":83},"index,follow",{"doc_id":128,"site_id":62},657903,1793091042,{"code":4,"msg":5,"data":131},{"doc_id":128,"user_id":132,"nickname":92,"user_avatar":133,"doc_module":4,"category_id":29,"category_name":30,"doc_title":65,"doc_description":67,"doc_content":134,"file_id":135,"file_url":136,"file_type":137,"file_size":138,"view_count":29,"is_deleted":4,"is_public":8,"is_downloadable":8,"audit_status":8,"page_count":139,"language":140,"language_code":63,"site_id":62,"html_lang":63,"table_of_contents":141,"faqs":142,"seo_title":143,"seo_description":67,"update_tm":144,"read_time":26},7971474920318,"https://ap-avatar.wpscdn.com/avatar/74000ee537e6b0ca360?x-image-process=image/resize,m_fixed,w_180,h_180&k=1788430171632181674","Fire Opal  \nBill Attwell  \nNorth York Faceting Guild(Toronto)  \n1)Terminology  \nFaceters know the white opal with its play of colour, but fewer know of the black opal on the right.  \nEbay  \nFire opal is very different. The word ‘fire’ in fire opal does not refer to the traditional use of the word. In fact, too many faceters confuse the traditional use of the word with play of colour.  \nThe term‘fire’ refers to the display of multcolours on the surface of the gem caused by dispersion.  \nDispersion leads to the separation of the component colours of white light as they pass through the gem.  \nUsed with permission  \nHerbst, Tom, Amateur Gemstone Faceting Vol 2, Fig 12:22  \nOne can see the fire on the surface of this cerrusite gem in Toronto’s Royal Ontario Museum, called “Light of the Desert”.  \nPlay of colour is the mult-colours seen inside opal not on its surface. It is caused by diffraction.  \nDiffraction occurs when the ray of white light separates its component colours by reflecting off of small similarly-sized spheres arranged in parallel lines to each other.  \n[geo.arizona.edu](geo.arizona.edu)  \nTherefore, fire opal has no fire and most have no play of colour.  \n‘Fire’ in fire opal refers to the body of colours.  \nGem Rock Auctions  \nMexican red fire opal octagon-5.74ct  \nAJS Gems  \nFire opal has orange, red and yellow colours, said to bethe colours of flames in a fire  \n6.30 Ct Ethiopian Welo  \nFire Opal Ebay  \nPlay of colour exhibited in fire opal.  \nOpal Auctions  \nA 3 carat fire opal rough  \nA faceter will want to orient the table parallel to the plane of diffraction in order to allow the reflected but separated light rays. to return through the table.  \nFaceters will note the misuse of the name ‘fire opal in the jewellery trade and among the public.  \nThis example is referred to on Alibaba by Aini Gems as fire black opal.  \nClearly, it is a black opal.  \nJust as opal when it has play of colour is called precious opal, so, technically, fire opal which has play of colour is named precious fire opal.  \nEvina  \nWith or without play of colour, fire opal can make gorgeous jewellery  \n2)Hardness  \nThe faceter should not avoid fire opal because of its hardness. Fire opal is too beautiful to avoid this experience. Faceters simply need to take care when cutting fire opal.  \nSince the hardness of fire opal is 5.5-6 on the Mohs Scale, which is approximately the hardness of glass, one has to be careful not to overcut the facets, particularly the smaller ones. As our recently deceased member, Konrad Widmaier, said last year about faceting fire opal,‘Be very careful”  \nThought has to be given to the use of fire opal gems. Which of the two types of settings below is better for opal?  \nHqdefault  \nEarrings, pendants and broaches preserve fire opal gems better than rings. Fire opal gems can be easily scratched when set in rings. This gem species will always be used in rings, though, but should not be worn constantly or in rough situations.  \n3)Brittleness  \nBrittleness is a definite concern but manageable as well.  \nMember Bill Orlowski said “Only start with 1200grit, use slow speed(300rpm) and a light touch”. Jim Wiklund wrote “only use a 340 or 600 grit lap if you have a large piece of rough, and want to preform it.”  \nOne can use 600 grit for fine  \nwork, such as with this 600  \ngrit temporary culet.  \nHowever, facet with slow to  \nmoderate speed with care.  \nGreat care was taken in placing this temporary point on the lap to create the permanent culet at a different angle.  \nA hard landing on the lap at a higher angle could result in a broken tip.  \nThus, gentleness   , a light touch    \nThe brittleness of fire opal ought to be kept in mind when choosing settings for rings.  \nNote how the girdle is protected.  \nA bezel setting would be worthwhile to consider.  \nHowever, keep perspective in mind. Look at all the rings on the market without a bezel setting.  \nAmazon  \nBrittleness should guide design selection, too. It is obvious whic","cbCaigDBnCrZztm5","https://ap.wps.com/l/cbCaigDBnCrZztm5","pdf",1572546,24,"English","# 1) Terminology\n## Definition of fire opal terms\n## Fire vs play of colour\n## Dispersion and diffraction mechanisms\n# 2) Hardness\n## Mohs hardness guidance\n## Cutting and facet care\n## Recommended setting considerations\n# 3) Brittleness\n## Managing brittleness during faceting\n## Lap speed, grit, and technique\n## Design and setting selection\n# 4) Design Selection\n## Brilliance and light return\n## Crown and pavilion optics\n## Pavilion angle “sweet spot”","[{\"question\":\"What does “fire” mean in fire opal, and how is it different from play of colour?\",\"answer\":\"In fire opal, “fire” refers to multicolours displayed on the gem’s surface due to dispersion. Play of colour refers to multicolours seen inside the opal, caused by diffraction.\"},{\"question\":\"Why do faceters need to orient the stone table parallel to the plane of diffraction?\",\"answer\":\"The orientation helps reflected but separated light rays return through the table, improving the desired optical outcome when cutting the facets.\"},{\"question\":\"How should hardness and brittleness concerns affect faceting and jewelry settings?\",\"answer\":\"Hardness (about 5.5–6 Mohs) requires careful cutting to avoid overcutting facets, especially smaller ones. Brittleness can be managed with gentle technique (e.g., grit choice and slow/moderate speeds) and by choosing settings that better protect the stone, such as considering bezels over rings.\"}]","Fire Opal - Bill Attwell - 1) Terminology | PDF",1792993853]