Replacement degree of Al3+ and Cr/V ratio in high-V emeralds from Malipo, Yunnan, China

Bai, Feng; Pan, Haihua; Li, Xuemei

doi:10.1007/s12517-019-4465-2

Cited by 4 publications

(3 citation statements)

References 12 publications

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“…Trace elements of Dayakou samples in the diagram include light elements (LE: Li, B), incompatible elements (IE: Cs−Ti), and transition metal chromophoric elements (CTE: Cr and V). Other trace elements results from worldwide V-dominant emeralds are summarized from the previous work reported by [16,20,21,42].…”

Section: Trace Elements From La-icp-ms Analysismentioning

confidence: 99%

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Major and Trace Element Geochemistry of Dayakou Vanadium-Dominant Emerald from Malipo (Yunnan, China): Genetic Model and Geographic Origin Determination

Zheng

Guo

2019

Minerals

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Emerald from the deposit at Dayakou is classified as a vanadium-dominant emerald together with Lened, Muzo, Mohmand, and Eidsvoll emeralds. Although previous studies defined these V-dominant emeralds and traced the genesis of the Dayakou deposit, there has not been any systematic comparison or discrimination on V-dominant emeralds from these deposits. The origin of the parental fluid and the crystallization process of the Dayakou emerald remain controversial. In this study, both major and trace element signatures of 34 V-dominant samples from Dayakou are analyzed through electron microprobe analysis (EMPA) and laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS). Dayakou emeralds are characterized by high ratios of V/Cr and the enrichment of Li, Cs, W, Sn, and As. These geochemical fingerprints indicate a parental fluid of an Early Cretaceous early-stage granitic fluid associated with Laojunshan granite. The considerable concentration variation of Rb, Cs, Ga and the presence of V-rich oxy-schorl-dravite inclusions in a color zoned sample suggest two generations of emerald precipitation. Thus, a more detailed idealized mineralization model for the Dayakou deposit is proposed. A series of plots, such as Rb vs. Cs, V vs. V/Cr, LILE vs. CTE, and Li vs. Sc, are constructed to discriminate the provenance of V-dominant emeralds. Minerals 2019, 9, 777 2 of 29 summarized emerald deposits worldwide and collected their chemical compositions. They defined Dayakou (China), Lened (Canada), Muzo (Colombia), Mohmand (Pakistan), and Eidsvoll (Norway) emeralds as typical V-dominant emeralds based on the greater content of V 2 O 3 than Cr 2 O 3 . Those V-dominant emeralds can be easily distinguished from Cr-dominant emeralds. However, there has not been a systematic comparison or discrimination of those V-dominant emeralds from various deposits. With regards to Dayakou emeralds, their chemical compositions have been recently reported [20], but not analyzed in detail. Trace elements of emerald are powerful indicators for determining the geographic provenance but the number of related studies is limited. For the first time, using Laser Ablation-Inductively Coupled Plasma-Mass Spectrometry (LA-ICP-MS) and Secondary Ion Mass Spectrometry (SIMS) techniques, [21] and [16] determined the origin of emeralds from several deposits by trace elements data, such as Li, B, Rb, Cs, V, Cr, Sc, Ga, etc. So far, only [20] has reported trace elements of Dayakou emerald, but their work focused on the Al 3+ replacement degree and Cr/V ratio. The geochemical fingerprints of the Dayakou emerald are not yet determined.Besides, the trace element geochemistry of emeralds was used for building the genetic model. B, Ga, Ba, Sr, and alkali elements Li, Cs, and Rb are regarded as indicators of parental fluid and the fractionation and evolution for pegmatite [3,4,22,23]. Reference [24] reported the formation conditions of Dayakou emerald, but the crystallization process and the sources of emerald-forming fluids have yet to be determined.In thi...

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Section: Trace Elements From La-icp-ms Analysismentioning

confidence: 99%

“…Data are normalized from wt.% microprobe analyses, with all Fe as FeO.Gray triangular area indicates that the content of V2O3 is greater than Cr2O3. Sources of data:[2,10,[14][15][16][17]19,20,[40][41][42][43][44].…”

mentioning

confidence: 99%

Major and Trace Element Geochemistry of Dayakou Vanadium-Dominant Emerald from Malipo (Yunnan, China): Genetic Model and Geographic Origin Determination

Zheng

Guo

2019

Minerals

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“…Colourless beryl with no impurity is called goshenite 6 . Emerald is coloured by Cr or V 7 . When Mn 3+ replaces Al 3+ , morganite is formed 8 .…”

Section: Introductionmentioning

confidence: 99%

Spectroscopy and chromaticity characterization of yellow to light-blue iron-containing beryl

Shang

Guo

Tang

2022

Sci Rep

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The chemical composition and influencing factors of the colour of 95 yellow to light blue iron-bearing beryl are studied through Electron Microprobe Analysis (EMPA), Energy-dispersive X-ray fluorescence (ED-XRF) spectroscopy, Fourier transform infrared (FTIR) spectroscopy, ultraviolet–visible (UV–vis) spectroscopy and X-Rite SP62 spectrophotometer. The intensities of the three characteristic hydroxyl stretching bands of the beryl from 3500 cm−1 to 3800 cm−1 prove they are low to medium levels of alkali bearing natural beryl. The wide absorption edge of 320 ~ 465 nm caused by the ultra-violet charge transfer from O2− to Fe3+ and the 650 nm absorption band in E//c-polarization caused by the intervalence charge transfer between Fe2+ and Fe3+ are the main factors affecting the colour of beryl. By applying CIE D65 standard light source and N9 Munsell neutral background as testing conditions, the colour parameters of 82 gem-quality beryl are tested. According to the results, iron-containing beryl colours are classified into yellow, yellowish-green, bluish-green, greenish-blue, and blue by the K-means cluster analysis method. The blue tone has a greater influence on the hue of beryl, while the yellow tone has a greater influence on the chroma. Iron content is higher in yellow and blue beryl. With the increase of iron content, the lightness of beryl decreased and the chroma increased.

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Crystallographic insights and crystal fractionation simulations of alkali- and water-bearing beryl: Implications for magmatic–hydrothermal evolution and Be enrichment mechanisms

Fan,

Xiong,

Brzozowski

et al. 2024

Ore Geology Reviews

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Replacement degree of Al3+ and Cr/V ratio in high-V emeralds from Malipo, Yunnan, China

Cited by 4 publications

References 12 publications

Major and Trace Element Geochemistry of Dayakou Vanadium-Dominant Emerald from Malipo (Yunnan, China): Genetic Model and Geographic Origin Determination

Major and Trace Element Geochemistry of Dayakou Vanadium-Dominant Emerald from Malipo (Yunnan, China): Genetic Model and Geographic Origin Determination

Spectroscopy and chromaticity characterization of yellow to light-blue iron-containing beryl

Crystallographic insights and crystal fractionation simulations of alkali- and water-bearing beryl: Implications for magmatic–hydrothermal evolution and Be enrichment mechanisms

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