New insights into chemical and spectroscopic characterization of beryl mineralization related to leucogranites in the west Wadi El Gemal area, southern Eastern Desert of Egypt

Mokhtar, Hesham; Surour, Adel A.; Azer, Mokhles K.; Ren, Mulan; Said, Amir

doi:10.1016/j.chemer.2023.125980

Cited by 2 publications

(3 citation statements)

References 42 publications

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“…Moreover, the very low content of Be in gneiss (1.9-2.2 ppm; [75]) The beryl (type I; Figure 8a,b) in Abu Rusheid pegmatites and pegmatitic quartz veins is typically euhedral with six-sided crystals, and forms a triple junction boundary with other silicates (Figure 3a,b), suggesting a magmatic-related origin. It shows notable depletion in MgO (up to 0.01 wt%) and Cr 2 O 3 (up to 0.03 ppm), but is rich in REEs that exhibit almost flat patterns (Figure 8a,b) relative to beryl compositions other places (Figure 1b), reflecting its granitic origin (e.g., [68]). This Abu Rusheid beryl is not only rich in LREE relative to HREE (Figure 8a), but also rich in Ba, Rb, Th, and U (Figure 8b).…”

Section: Genesis Of Beryl and Source Of Berylliummentioning

confidence: 99%

“…Beryl mineralization is relatively rare, and may be classified into beryl related to granitic intrusions, or beryl related to schists without pegmatites (e.g., [78,84]). Following this classification scheme, two modes of beryl occurrences are recognized in the SED of Egypt as follows: (1) schist-related emerald and (2) granite-related beryl of the Neoproterozoic age [2,6,7,11,18,63,68,72,75,85,86].…”

Section: Factors Controlling Beryl Distribution In the Sedmentioning

confidence: 99%

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The Geology and Mineral Chemistry of Beryl Mineralization, South Eastern Desert, Egypt: A Deeper Insight into Genesis and Distribution

Khedr,

Saleh,

Abdelfadil

et al. 2024

Minerals

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Beryl mineralization in the Nugrus-Sikait domain in the South Eastern Desert (SED) of Egypt occurs as disseminated crystals in granitic pegmatite and quartz, as well as pegmatite veins crosscutting mélange schist and ophiolitic rocks. When granitic pegmatite comes into contact with the ophiolitic rocks, phlogopite and amphibole schists are formed due to K metasomatism. The ophiolitic mélange is intruded by leucogranite and related pegmatite along the NNW to NW Nugrus shear zone. Beryl samples have been collected from Um Sleimat, Madinat Nugrus, Wadi Abu Rusheid, and Wadi Sikait. Major oxides and in situ trace and rare earth elements (REEs) of beryl and associated minerals were analyzed through EPMA and LA-ICP-MS, respectively. The investigated beryl, based on its color and chemical compositions, can be classified into the two following types: pegmatitic beryl (type I) and schist-related beryl (type II). The former is colorless to pale green, and is mainly restricted in pegmatite veins; it is poor in Cr2O3 (up to 0.03 wt%) and MgO (Nil). The latter, deep green in color, is rich in Cr2O3 (up to 0.27 wt%) and MgO (up to 2.71 wt%), and occurs within quartz veins, phlogopite schists, and tremolite schists. The abundant beryl mineralization in phlogopite schists and their related quartz veins suggests that granite and associated pegmatite are the source rocks for the Be-bearing fluids that migrate along the NW-SE trending deep-seated tectonic zone, such as the Nugrus shear zone. Therefore, the formation of beryl in schists is attributed to the interaction of granitic/pegmatitic-derived Be-bearing fluids with serpentinite and gabbro interlayered with mélange schists. Variations in the trace and REE contents of both beryl types (I and II) indicate their two-stage formation from different compositions of Be-rich fluids, where light REEs, Zr, Nb, Ba, and Th decrease from type I beryl to type II. These two phases of beryl could be attributed to the magmatic/hydrothermal fluids associated with the pegmatite emplacement. The early phase of the late-stage magmatic-derived fluids was closely related to magma evolution and pegmatite formation, forming euhedral type I beryl. The late phase of pegmatite-derived fluids was mixed with serpentinite/schist-derived fluids that cause high V and Cr content in type II beryl. The composition of parent magmas of felsic rocks, the high degree of magma fractionation or the late stage melts, fluid compositions (rich in Be, Li, Cs, Rb, K), and alkali metasomatism, as well as the linear NW-SE trending deep-seated shear zone, are all factors possibly influencing beryl mineralization in the SED of Egypt.

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Section: Genesis Of Beryl and Source Of Berylliummentioning

confidence: 99%

Section: Factors Controlling Beryl Distribution In the Sedmentioning

confidence: 99%

The Geology and Mineral Chemistry of Beryl Mineralization, South Eastern Desert, Egypt: A Deeper Insight into Genesis and Distribution

Khedr,

Saleh,

Abdelfadil

et al. 2024

Minerals

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“…In addition, the family of beryl comprises many coloured varieties (Table 1), making them popular gemstones, such as heliodor (yellow to greenish yellow), golden beryl (golden), morganite (pink to orange-pink), emeralds (green), red beryl (red to magenta) and aquamarine (blue to green-blue). In fact, emerald is one of the most important gemstones in the gemstone industry (Bersani et al, 2014;Groat and Turner, 2022;Khaleal et al, 2022;Mokhtar et al, 2023) and comes third after diamond and ruby in terms of value (Groat et al, 2008). The colours of beryl are rooted in the incorporation of transition metal ions, such as Cr or V, into the structure of beryl.…”

Section: Introductionmentioning

confidence: 99%

Incorporation and substitution of ions and H₂O in the structure of beryl

Hanser,

Häger,

Botcharnikov

2024

Eur. J. Mineral.

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Abstract. Incorporation of ions into the crystal structure of beryl (Be3Al2[Si6O18]) can take place by direct ion-to-ion substitution of the framework components Al3+, Be2+ and Si4+ or by occupation of interstitial or structural channel sites. The most common impurities in beryl include transition metals, alkalis and H2O. It is accepted that the transition metals Mn, Cr and V directly substitute for Al at the octahedral site and induce colour. Similarly, the octahedral site can host Fe instead of Al. Nevertheless, it is shown that it remains disputed whether Fe can also be present at the tetrahedral, interstitial, or channel sites, and opposing hypotheses exist regarding these possibilities. However, in the case of Fe, not only the possible occupation of these sites remains under debate, but also their influence on the subsequent colour of beryl. Similarly, the residence of Li in the channels and at the Be tetrahedral or interstitial tetrahedral sites is still under debate. The presence of more than two types of H2O (type I and type II) in the structural channels of beryl is also unclear. This article aims to give an overview on the consensus and on the current debates found in the literature regarding these aspects. It mainly concentrates on the substitution by and the role of Fe ions and on channel occupancy by H2O.

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New insights into chemical and spectroscopic characterization of beryl mineralization related to leucogranites in the west Wadi El Gemal area, southern Eastern Desert of Egypt

Cited by 2 publications

References 42 publications

The Geology and Mineral Chemistry of Beryl Mineralization, South Eastern Desert, Egypt: A Deeper Insight into Genesis and Distribution

The Geology and Mineral Chemistry of Beryl Mineralization, South Eastern Desert, Egypt: A Deeper Insight into Genesis and Distribution

Incorporation and substitution of ions and H₂O in the structure of beryl

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New insights into chemical and spectroscopic characterization of beryl mineralization related to leucogranites in the west Wadi El Gemal area, southern Eastern Desert of Egypt

Cited by 2 publications

References 42 publications

The Geology and Mineral Chemistry of Beryl Mineralization, South Eastern Desert, Egypt: A Deeper Insight into Genesis and Distribution

The Geology and Mineral Chemistry of Beryl Mineralization, South Eastern Desert, Egypt: A Deeper Insight into Genesis and Distribution

Incorporation and substitution of ions and H2O in the structure of beryl

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Incorporation and substitution of ions and H₂O in the structure of beryl