Inclusions in Taaffeites from Sri Lanka

Gunawardene, Mahinda

doi:10.5741/gems.20.3.159

Cited by 3 publications

(2 citation statements)

References 7 publications

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“…Dolomite was frequently found in the spinel from Mogok, Myanmar [1 Therefore, dolomite was inferred as a characteristic inclusion of spinel from Mogok, M anmar. For taaffeite, dolomite may be a typical inclusion in this region, but it has ne been found in other areas [8,9,13].…”

Section: Identification Of the Inclusionsmentioning

confidence: 88%

“…Taaffeite is reportedly produced in Tanzania, Sri Lanka, Myanmar, and China [7 According to previous studies, the refractive index of taaffeite is 1.715-1.735, and its cific gravity is 3.57-3.78 [7][8][9][10]. The inclusions in taaffeites from Sri Lanka are zircon, nesite, feldspar, apatite, muscovite, spinel, phlogopite, fingerprint-like inclusions, he fissures, and negative crystals with multi-phase inclusions [9,10,12,13]. Healed fiss are seen in taaffeite samples from Myanmar [7].…”

Section: Introductionmentioning

confidence: 99%

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Gemological and Luminescence Characteristics of Taaffeites from Mogok, Myanmar

Lin

Zhang

et al. 2023

Minerals

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Taaffeite is a rare gem that has been found in different localities such as Tanzania, Sri Lanka, China, and Mogok, Myanmar. In this study, thirty-two taaffeite samples from Mogok, Myanmar, were investigated by conventional gemological testing, laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS), Raman spectrometry, and fluorescence spectrometry. Through microscopic observations, various types of inclusions were observed in these taaffeites, including irregular inclusions, orange and brown intrusions, black dotted and flake inclusions, healed fissures, tubular inclusions, fingerprint inclusions, and multi-phase inclusions. The Raman spectra demonstrated that the inclusions were mainly calcite, forsterite, celestite, graphite, dolomite, and transparent tubular or columnar inclusions filled with CO2. In previous studies, taaffeite showed inert or chalky fluorescence under long-wave ultraviolet (LWUV) light and inert fluorescence under short-wave ultraviolet (SWUV) light. In this study, the taaffeite samples revealed different fluorescence phenomena under ultraviolet light. Thirty-two taaffeite samples were classified into four categories according to their fluorescence under LWUV: orange-red, pink, green, and blue-white fluorescence. Under SWUV, all samples presented inert to bright pink fluorescence. Two-dimensional fluorescence spectra were obtained through a fluorescence spectrometer. For the samples with orange-red and pink fluorescence under LWUV, two-dimensional fluorescence spectra showed that peaks at 686 nm and 690 nm (in the red region) were strong. For the samples with green and blue-white fluorescence under LWUV, peaks at 439 nm and 464 nm (in the blue region) were strong, peaks at 507–515 nm (in the green region) were relatively weak, and peaks at 686 and 690 nm (in the red region) were very weak. Combined with the data from LA-ICP-MS, it is speculated that Cr3+ was responsible for samples having orange-red and pink fluorescence, that Mn2+ was responsible for samples having green fluorescence, and that Fe inhibited the generation of fluorescence.

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Section: Identification Of the Inclusionsmentioning

confidence: 88%