Emeralds from the Most Important Occurrences: Chemical and Spectroscopic Data

Abstract

The present study applied LA–ICP-MS on gem-quality emeralds from the most important sources (Afghanistan, Brazil, Colombia, Ethiopia, Madagascar, Russia, Zambia and Zimbabwe). It revealed that emeralds from Afghanistan, Brazil, Colombia and Madagascar have a relatively lower lithium content (7Li < 200 ppmw) compared to emeralds from other places (7Li > 250 ppmw). Alkali element contents as well as scandium, manganese, cobalt, nickel, zinc and gallium can further help us in obtaining accurate origin information for these emeralds. UV-Vis spectroscopy can aid in the separation of emeralds from Colombia and Afghanistan from these obtained from the other sources as the latter present pronounced iron-related bands. Intense Type-II water vibrations are observed in the infrared spectra of emeralds from Madagascar, Zambia and Zimbabwe, as well as in some samples from Afghanistan and Ethiopia, which contain higher alkali contents. A band at 2818 cm−1, supposedly attributed to chlorine, was observed only in emeralds from Colombia and Afghanistan. Samples with medium to high alkalis from Ethiopia, Madagascar, Zambia and Zimbabwe can also be separated from the others by Raman spectroscopy based on the lower or equal relative intensity of the Type I water band at around 3608 cm−1 compared to the Type II water band at around 3598 cm−1 band (with some samples from Afghanistan, Brazil and Russia presenting equal relative intensities).

Inclusion and Trace Element Characteristics of Emeralds from Swat Valley, Pakistan

“…Several published studies represent an early attempt to use trace elements for provenance purposes (Saeseaw et al, 2014(Saeseaw et al, , 2019Carlo et al, 2018), but the data for Swat emeralds is scarce. In this study, 27 spots on 11 regular Swat emeralds were analyzed via LA-ICP-MS. Logarithm plots of trace elements were applied to detect possible correlations when distinguishing geographic origin, so adding LA-ICP-MS data from other main emerald deposits in the world is necessary, such as Colombia, Kafubu from Zambia, Brazil (Zwaan et al, 2012), Panjshir from Afghanistan, Swat from Pakistan (Carlo et al, 2018), Khaltaro from Pakistan (Laurs et al, 1996), Russia (Saeseaw et al, 2019;Carlo et al, 2018;Karampelas et al, 2019;all averages), Ethiopia (Saeseaw et al, 2019;Carlo et al, 2018;Karampelas et al, 2019;all averages), Egypt (Carlo et al, 2018), India (Carlo et al, 2018, and Malipo from China (Zheng et al, 2019). The inclusions of Ethiopian and Russian emeralds (Saeseaw et al, 2019) Laurs et al (1996), Zwaan et al (2012), andZheng et al (2019).…”

“…80.64 ppmw V; avg. 1600.67 ppmw Fe) emeralds(Karampelas et al, 2019).The plots of Cs versus Rb and Li versus Cs showed a positive correlation (figure19 and 20), but there is some overlap for emeralds from Swat Valley, Russia, Ethiopia, India, Egypt, and Zambia. The plot of Li versus Sc proved useful in separating Swat Valley from…”

Spectroscopic Analysis for Harnessing the Quality and Potential of Gemstones for Small and Medium-Sized Enterprises (SMEs)

“…e color of the natural gemstones is the basic factor for determining the quality and commercial significance, and there are multiple factors for the origin of these colors in gem minerals [2,[5][6][7]. Geologists have identified the following five mechanisms which are responsible for the color of gemstones [8][9][10].…”

Editorial for Special Issue “Mineralogy and Geochemistry of Gems”

“…Giuliani et al [11] and Karampelas et al [12] present studies on emeralds; the bluish-green to green to yellowish-green variety of beryl coloured by chromium and sometimes vanadium. The first group of authors in their review proposed an enhanced classification for emerald deposits based on the geological environment (magmatic or metamorphic), host-rock types (mafic-ultramafic rocks, sedimentary rocks, and granitoids), degree of metamorphism, styles of mineralization (veins, pods, metasomatites, shear zone) as well as the type of gem-forming fluids and their temperature, pressure, and composition [11].…”

“…The first group of authors in their review proposed an enhanced classification for emerald deposits based on the geological environment (magmatic or metamorphic), host-rock types (mafic-ultramafic rocks, sedimentary rocks, and granitoids), degree of metamorphism, styles of mineralization (veins, pods, metasomatites, shear zone) as well as the type of gem-forming fluids and their temperature, pressure, and composition [11]. Karampelas et al [12] present an applied study that provides a chemical and spectroscopic analysis of gem-quality emeralds from the most important sources (i.e., Afghanistan (Panjsher Valley), Brazil (Itabira), Colombia (Coscuez), Ethiopia (Shakisso), Madagascar (Mananjary), Russia (Ural mountains), Zambia (Kafubu) and Zimbabwe (Sandawana)). Their study demonstrates how these different analyses can collectively be used to distinguish them from one another (i.e., geographic gem determination).…”