{"product_id":"gia-dichroscope-1970s-90s","title":"GIA Dichroscope (1970s-90s)","description":"\u003cdiv class=\"n6owBd awi2gc\" data-sfc-cp=\"\" data-sfc-root=\"c\" data-hveid=\"CAAICRAA\" data-complete=\"true\" data-processed=\"true\"\u003e\n\u003cmeta charset=\"utf-8\"\u003e\n\u003cdiv class=\"n6owBd awi2gc\" data-sfc-cp=\"\" data-sfc-root=\"c\" data-hveid=\"CAAICBAA\" data-complete=\"true\" data-processed=\"true\"\u003e\n\u003cmeta charset=\"utf-8\"\u003e\n\u003cdiv class=\"n6owBd awi2gc\" data-sfc-cp=\"\" data-sfc-root=\"c\" data-hveid=\"CAAICBAA\" data-complete=\"true\" data-processed=\"true\"\u003e\n\u003cmeta charset=\"utf-8\"\u003e\n\u003cdiv class=\"n6owBd awi2gc\" data-sfc-cp=\"\" data-sfc-root=\"c\" data-hveid=\"CAAICBAA\" data-complete=\"true\" data-processed=\"true\"\u003e\n\u003cmeta charset=\"utf-8\"\u003e\n\u003cdiv class=\"n6owBd awi2gc\" data-sfc-cp=\"\" data-sfc-root=\"c\" data-hveid=\"CAAIDBAA\" data-complete=\"true\" data-processed=\"true\"\u003eThe \u003cspan class=\"rQesXe MPyX\"\u003eGIA Pocket Calcite Dichroscope\u003c\/span\u003e stands as an iconic handheld diagnostic tool engineered during the peak operational expansion of the Gemological Institute of America's manufacturing division. Released as a core component of the institutional Graduate Gemologist training kits, this student model was distributed directly from GIA's landmark international headquarters located at \u003cspan class=\"rQesXe MPyX\"\u003e1660 Stewart Street, Santa Monica, CA 90404\u003c\/span\u003e. When it first hit the global market in the late 1970s, the precision field instrument retailed between \u003cspan class=\"rQesXe MPyX\"\u003e$45.00 and $65.00 USD\u003c\/span\u003e, serving as an accessible benchmark that democratized portable optical testing during the \"GIA Gem Instruments\" era (1966–1999).\u003c!--TgQPHd|||[]--\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"yhAwj\" data-sfc-cp=\"\" data-sfc-root=\"c\" data-complete=\"true\" data-processed=\"true\" data-sfc-inited=\"2\"\u003e\u003c!--TgQPHd|||[]--\u003e\u003c\/div\u003e\n\u003cdiv class=\"ZLzG0d ncoeY E8xBUb\" role=\"heading\" aria-level=\"4\" data-animation-nesting=\"\" data-sfc-cp=\"\" data-wiz-attrbind=\"aria-level=PCA0ce_20\/fLk2Md\" data-sfc-root=\"c\" data-hveid=\"CAAIDRAA\" data-complete=\"true\" data-processed=\"true\" data-sae=\"\"\u003e\n\u003cbr\u003e\u003c!--TgQPHd|||[[2,[null,null,1,null,null,null,null,null,null,null,null,null,[351768,null,0]],[],null,1]]--\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"ZLzG0d ncoeY E8xBUb\" role=\"heading\" aria-level=\"4\" data-animation-nesting=\"\" data-sfc-cp=\"\" data-wiz-attrbind=\"aria-level=PCA0ce_20\/fLk2Md\" data-sfc-root=\"c\" data-hveid=\"CAAIDRAA\" data-complete=\"true\" data-processed=\"true\" data-sae=\"\"\u003e\u003c\/div\u003e\n\u003cdiv class=\"n6owBd awi2gc\" data-sfc-cp=\"\" data-sfc-root=\"c\" data-hveid=\"CAAIDhAA\" data-complete=\"true\" data-processed=\"true\"\u003eAt its operational core, this compact device utilizes a classic \u003cspan class=\"rQesXe MPyX\"\u003eHaidinger architecture\u003c!--TgQPHd|||[]--\u003e\u003c\/span\u003e to determine the presence of pleochroism in colored gemstones. When light passes through an unknown sample and enters the barrel via a micro-pinhole aperture, it interacts with an internal, high-clarity \u003cspan class=\"rQesXe MPyX\"\u003eIceland spar (calcite) rhomboid prism\u003c\/span\u003e. The extreme birefringence of the natural calcite crystal splits the incoming light path into two orthogonally polarized rays. By displaying these twin rays side-by-side as distinct, perfectly isolated color windows in the eyepiece, the device allows gemologists to safely identify doubly refractive species or instantly unmask single-refractive simulants like garnet or glass.\u003c!--TgQPHd|||[]--\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"yhAwj\" data-sfc-cp=\"\" data-sfc-root=\"c\" data-complete=\"true\" data-processed=\"true\" data-sfc-inited=\"2\"\u003e\u003c!--TgQPHd|||[]--\u003e\u003c\/div\u003e\n\u003cdiv class=\"ZLzG0d ncoeY E8xBUb\" role=\"heading\" aria-level=\"4\" data-animation-nesting=\"\" data-sfc-cp=\"\" data-wiz-attrbind=\"aria-level=PCA0ce_25\/fLk2Md\" data-sfc-root=\"c\" data-hveid=\"CAAIDxAA\" data-complete=\"true\" data-processed=\"true\" data-sae=\"\"\u003e\n\u003cbr\u003e\u003c!--TgQPHd|||[[2,[null,null,1,null,null,null,null,null,null,null,null,null,[351768,null,0]],[],null,1]]--\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"ZLzG0d ncoeY E8xBUb\" role=\"heading\" aria-level=\"4\" data-animation-nesting=\"\" data-sfc-cp=\"\" data-wiz-attrbind=\"aria-level=PCA0ce_25\/fLk2Md\" data-sfc-root=\"c\" data-hveid=\"CAAIDxAA\" data-complete=\"true\" data-processed=\"true\" data-sae=\"\"\u003e\u003c\/div\u003e\n\u003cdiv class=\"n6owBd awi2gc\" data-sfc-cp=\"\" data-sfc-root=\"c\" data-hveid=\"CAAIEBAA\" data-complete=\"true\" data-processed=\"true\" aria-owns=\"action-menu-parent-container\"\u003eThe physical design of this specific generation highlights an intentional engineering shift away from the heavy, polished brass housings of the mid-20th century. Machined from a lightweight metal alloy with a sleek, protective matte-black anodized barrel, the body integrates a \u003cstrong class=\"rQesXe MPyX\" data-sfc-cp=\"\" data-sfc-root=\"c\" data-complete=\"true\" data-processed=\"true\"\u003eheavily cross-knurled eyepiece ring\u003c!--TgQPHd|||[]--\u003e\u003c\/strong\u003e featuring a textured diamond pattern to allow for highly precise, non-slip focal adjustments. Opposite the focusing sleeve, the cap is capped with a distinctive, factory-milled \u003cstrong class=\"rQesXe MPyX\" data-sfc-cp=\"\" data-sfc-root=\"c\" data-complete=\"true\" data-processed=\"true\"\u003ehexagon nut cap structure\u003c!--TgQPHd|||[]--\u003e\u003c\/strong\u003e designed explicitly as an anti-roll mechanism to prevent the tool from sliding off slanted jeweler benches. This rugged design contrasts sharply with modern, smooth-barreled pocket variants, offering a maintenance-free layout that withstands decades of active trade room use.\u003c\/div\u003e\n\u003cbr\u003e\u003cmeta charset=\"utf-8\"\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"n6owBd awi2gc\" data-sfc-cp=\"\" data-sfc-root=\"c\" data-hveid=\"CAAICxAA\" data-complete=\"true\" data-processed=\"true\"\u003e\n\u003cbr data-sfc-root=\"c\" data-sfc-pl=\"|||[]\" data-complete=\"true\" data-processed=\"true\"\u003e\u003cbr\u003e\u003cspan\u003e\u003c\/span\u003e\u003c!--TgQPHd|||[]--\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"yhAwj\" data-sfc-cp=\"\" data-sfc-root=\"c\" data-complete=\"true\" data-processed=\"true\" data-sfc-inited=\"2\"\u003e\u003c!--TgQPHd|||[]--\u003e\u003c\/div\u003e\n\u003cdiv class=\"AHmQrc\" data-sfc-cp=\"\" data-sfc-root=\"c\" data-hveid=\"CAAIDBAA\" data-complete=\"true\" data-processed=\"true\" data-sfc-inited=\"2\"\u003e\n\u003cdiv class=\"n6owBd awi2gc\" data-sfc-cp=\"\" data-sfc-root=\"c\" data-hveid=\"CAAIDBAB\" data-complete=\"true\" data-processed=\"true\"\u003e\u003c\/div\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"yhAwj\" data-sfc-cp=\"\" data-sfc-root=\"c\" data-complete=\"true\" data-processed=\"true\" data-sfc-inited=\"2\"\u003e\u003c!--TgQPHd|||[]--\u003e\u003c\/div\u003e","brand":"Gems.studio","offers":[{"title":"Default Title","offer_id":68057437143360,"sku":null,"price":0.0,"currency_code":"CAD","in_stock":false}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0963\/0397\/2672\/files\/GIADichroscope7090_1.avif?v=1794106035","url":"https:\/\/gems.studio\/products\/gia-dichroscope-1970s-90s","provider":"Gems.studio","version":"1.0","type":"link"}