{"id":15367,"date":"2022-05-17T10:12:27","date_gmt":"2022-05-17T04:42:27","guid":{"rendered":"https:\/\/gjepc.org\/solitaire\/?p=15367"},"modified":"2022-05-17T10:12:30","modified_gmt":"2022-05-17T04:42:30","slug":"ssef-analyses-cobalt-blue-spinel-from-new-tanzanian-source","status":"publish","type":"post","link":"https:\/\/gjepc.org\/solitaire\/ssef-analyses-cobalt-blue-spinel-from-new-tanzanian-source\/","title":{"rendered":"SSEF Analyses Cobalt-Blue Spinel From New Tanzanian Source"},"content":{"rendered":"\n<p>For several months already a supply of blue cobalt-bearing spinel has been appearing in the gem trade, including some stones of remarkable size \u2013 up to 40 carats \u2013 and quality, the Swiss Gemmological Institute SSEF said. According to information from reliable sources, the source of the new find is a deposit located about 20km south-east of Mahenge, Tanzania, which for more than 20 years has been known for its red to pinkish red spinel of exceptional quality.<\/p>\n\n\n\n<p>Detailed analyses of a selection of blue spinels from the newly reported source, conducted at SSEF, has revealed that they contain cobalt as a main colouring element (chromophore), in combination with iron. This is similar to cobalt-spinel materials from sources in Sri Lanka, Pakistan and Vietnam.<\/p>\n\n\n\n<p>Interestingly, cobalt-blue spinel from the source in Tanzania contains quite characteristic inclusion features, such as oriented geometric lamellae with interference colours (Figure 2), together with lines of fine particles, reported SSEF. Similar inclusion features have been described in red Tanzanian spinel from Morogoro. Additionally, colourless apatite and clusters of small zircon inclusions were identified by Raman spectroscopy.<\/p>\n\n\n\n<div class=\"wp-block-image\"><figure class=\"aligncenter size-large is-resized\"><a href=\"https:\/\/gjepc.org\/solitaire\/wp-content\/uploads\/2022\/05\/01pic-4.jpg\" rel=\"mfp\"><img loading=\"lazy\" decoding=\"async\" src=\"data:image\/gif;base64,R0lGODlhAQABAAAAACH5BAEKAAEALAAAAAABAAEAAAICTAEAOw==\" data-src=\"https:\/\/gjepc.org\/solitaire\/wp-content\/uploads\/2022\/05\/01pic-4.jpg\" alt=\"\" class=\"wp-image-15368 lazyload\" width=\"488\" height=\"413\" data-sizes=\"auto\" data-srcset=\"https:\/\/gjepc.org\/solitaire\/wp-content\/uploads\/2022\/05\/01pic-4.jpg 500w, https:\/\/gjepc.org\/solitaire\/wp-content\/uploads\/2022\/05\/01pic-4-300x254.jpg 300w, https:\/\/gjepc.org\/solitaire\/wp-content\/uploads\/2022\/05\/01pic-4-450x381.jpg 450w, https:\/\/gjepc.org\/solitaire\/wp-content\/uploads\/2022\/05\/01pic-4-225x190.jpg 225w, https:\/\/gjepc.org\/solitaire\/wp-content\/uploads\/2022\/05\/01pic-4-20x17.jpg 20w, https:\/\/gjepc.org\/solitaire\/wp-content\/uploads\/2022\/05\/01pic-4-113x96.jpg 113w\" sizes=\"auto, (max-width: 488px) 100vw, 488px\" \/><\/a><figcaption>Figure 2: Oriented lamellae with interference colours together with lines of fine particles are characteristic features of the newly reported cobalt-blue spinels from Tanzania. Photo: M.S. Krzemnicki, SSEF<\/figcaption><\/figure><\/div>\n\n\n\n<p>Gem-quality cobalt-blue spinels are highly sought-after and valued, and consequently have been studied extensively by SSEF, which has been offering origin determination for cobalt-blue spinel for many years.<\/p>\n\n\n\n<p>\u201cCobalt-blue spinel from this new source in Tanzania is a welcome and attractive addition to the trade\u201d, said Dr. Michael Krzemnicki, Director at the Swiss Gemmological Institute SSEF. \u201cIt is also fascinating material for us gemmologists to study, as these spinels display specific gemmological characteristics that are helpful for origin determination.\u201d<\/p>\n","protected":false},"excerpt":{"rendered":"<p>For several months already a supply of blue cobalt-bearing spinel has been appearing in the gem trade, including some stones of remarkable size \u2013 up to 40 carats \u2013 and quality, the Swiss Gemmological Institute SSEF said. According to information from reliable sources, the source of the new find is a deposit located about 20km&hellip;<\/p>\n","protected":false},"author":1,"featured_media":15369,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[83],"tags":[],"thb-sponsors":[],"class_list":["post-15367","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-bulletin"],"acf":[],"yoast_head":"<!-- This site is optimized with the Yoast SEO plugin v14.5 - https:\/\/yoast.com\/wordpress\/plugins\/seo\/ -->\n<title>SSEF Analyses Cobalt-Blue Spinel From New Tanzanian Source - Solitaire magazine is a International jewellery magazine - India\u2019s leading B2B gem and jewellery magazine<\/title>\n<meta name=\"robots\" content=\"index, follow\" \/>\n<meta name=\"googlebot\" content=\"index, follow, max-snippet:-1, max-image-preview:large, max-video-preview:-1\" \/>\n<meta name=\"bingbot\" content=\"index, follow, max-snippet:-1, max-image-preview:large, max-video-preview:-1\" \/>\n<link rel=\"canonical\" href=\"https:\/\/gjepc.org\/solitaire\/ssef-analyses-cobalt-blue-spinel-from-new-tanzanian-source\/\" \/>\n<meta property=\"og:locale\" content=\"en_US\" \/>\n<meta property=\"og:type\" content=\"article\" \/>\n<meta property=\"og:title\" content=\"SSEF Analyses Cobalt-Blue Spinel From New Tanzanian Source - Solitaire magazine is a International jewellery magazine - India\u2019s leading B2B gem and jewellery magazine\" \/>\n<meta property=\"og:description\" content=\"For several months already a supply of blue cobalt-bearing spinel has been appearing in the gem trade, including some stones of remarkable size \u2013 up to 40 carats \u2013 and quality, the Swiss Gemmological Institute SSEF said. 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