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Abstract: An on-line coupling between a continuous-flow sequential extraction (CFSE) unit and flow field-flow fractionation with cross flow matrix removal (FlFFF/CFM) with ICP-OES detection was developed for determination of metal leachability from soil. The use of high concentration of Mg(NO3)2 in exchangeable phase can cause undesirable matrix effects by shifting ionization equilibrium in the plasma, etc., resulting in a clear need for matrix removal. Therefore, the capability of FlFFF/CFM to remove Mg matrix ion from soil extract was evaluated. Poly(ethylene imine) (PEI) having molecular weight of 25,000Da was added to form complexes with analyte elements (Cu, Mn, Pb, and Zn) but not the matrix element (Mg). The free Mg matrix ions were then removed by filtering off through the ultrafiltration membrane, having a 1000-Da molecular weight cut-off, inside the FlFFF channel. With the use of FlFFF/CFM, matrix removal efficiency was approximately 83.5%, which was equivalent to approximately 6-fold dilution of the matrix ion. The proposed hyphenated system of CFSE and FlFFF/CFM with ICP-OES detection was examined for its reliability by checking with SRM 2710 (a highly contaminated soil from Montana). The metal contents determined by the proposed method were not significantly different (at 95% confidence) from the certified values. [Copyright &y& Elsevier]

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). [ABSTRACT FROM AUTHOR]

The present study applied Laser Ablation-Inductively Coupled Plasma-Mass Spectrometry (LA-ICP-MS) on a large number of natural and cultured pearls from saltwater and freshwater environments, which revealed that freshwater (natural and cultured) pearls contain relatively higher quantities of manganese (Mn) and barium (Ba) and lower sodium (Na), magnesium (Mg) and strontium (Sr) than saltwater (natural and cultured) pearls. A few correlations between the host animal's species and chemical elements were found; some samples from Pinctada maxima (P. maxima) are the only studied saltwater samples with 55Mn >20 ppmw, while some P. radiata are the only studied saltwater samples with 24Mg <65 ppmw and some of the P. imbricata are the only studied saltwater samples with 137Ba >4.5 ppmw. X-ray luminescence reactions of the studied samples has confirmed a correlation between its yellow-green intensity and manganese content in aragonite, where the higher Mn2+ content, the more intense the yellow-green luminescence becomes. Luminescence intensity in some cases is lower even if manganese increases, either because of pigments or because of manganese self-quenching. X-ray luminescence can be applied in most cases to separate saltwater from freshwater samples; only samples with low manganese content (55Mn <50 ppmw) might be challenging to identify. One of the studied natural freshwater pearls contained vaterite sections which react by turning orange under X-ray due to a different coordination of Mn2+ in vaterite than that in aragonite. [ABSTRACT FROM AUTHOR]

Natural yellow sapphires are colored by one of two entirely different chromophores or by a combination of the two. These two chromophores are iron (Fe3+) and a trapped hole paired with iron (h•-Fe3+). The color saturation of the Fe3+ chromophore, as previously documented, does not linearly depend on its areal density, unlike the other five chromophores in natural corundum. It exhibits a complex dependence on areal density, a relationship that is explored here. Low-iron-content natural yellow sapphires are colored solely by the h•-Fe3+ chromophore. The yellow sapphires from Sri Lanka are colored in this way. Some of the basalt-hosted high-iron sapphires from Australia and Thailand are colored by h•-Fe3+ in addition to Fe3+. Natural sapphires that are colorless or weakly yellow often develop strong yellow coloration via heat treatment. They depend on formation of the h•-Fe3+ chromophore for that change. In these natural stones that respond to heat treatment, one of two different internal chemistries is present, which must be altered to bring about the color enhancement. These two chemistries, which require two different heat treatment processes, are presented. The diffusion of beryllium into various types of sapphire can shift their chemistry from donor- to acceptor-dominated, forming the trapped hole, h•, which pairs with iron to produce the intense yellow coloration. Although crystals with the h•-Fe3+ chromophore were grown as a part of our study, synthetic yellow sapphires are not often colored by the same chromophores of natural sapphires. They are usually colored by the Ni3+ chromophore or by Ni3+ and Cr3+. Somewhat surprisingly, the color saturation of Czochralski-grown nickel-doped sapphire can sometimes be enhanced by heat treatment. [ABSTRACT FROM AUTHOR]

The article offers world gemmology news briefs as of September 2016. The discovery of amazonite, jadeite, topazolite, demantoid, and labradorite has demonstrated the importance of systematic research of the Mexican subsoil. A team of Gemological Institute of America (GIA) field gemologists visited Tanzanian mines to collect ruby and sapphire for reference collection. A yellow sapphire from Thailand has also showed a spectrum associated with high-temperature heat treatment of blue sapphire.

Until now, the observation of three-phase inclusions in emeralds has been considered a potential indicator of Colombian origin. Nevertheless, emeralds from Afghanistan (Panjshir Valley), China (Davdar), and Zambia (Kafubu and a new deposit at Musakashi) may contain three-phase inclusions resembling those often found in specimens from Colombian deposits (Muzo, Chivor, La Pita, Coscuez, and Penas Blancas). This article presents detailed photomicrographs of samples from these localities, with a focus on their multiphase inclusions. Also investigated are spectroscopic features and trace-element data. For the gemologist studying the origin of emeralds hosting three-phase inclusions, a powerful set of tools to aid in this determination comes from the combination of detailed microscopic examination, UV-Vis-NIR and FTIR spectroscopy, and LA-ICP-MS trace-element analysis. [ABSTRACT FROM AUTHOR]

The aticle offers updates concerning gems and gemology from around the world as of December 2015. These include the discovery of demantoid garnet with giant fluid inclusion, the discovery of gem-quality grandidierite from Madagascar, and the recognition of the andradite varieties melanite, topazolite and demantoid.

The article focuses on findings from studies of several diamonds from different laboratories. Topics discussed include the baroque-shaped pearls through inductively coupled plasma?mass spectrometry (ICP-MS) and energy-dispersive X-ray fluorescence (EDXRF), the damaged nacre pearls, the natural diamonds coated with calcium fluoride (CaF2) which accounts for its pink color, a fish-like inclusion on diamond, the artificially irradiated diamond and a fancy dark orangy brown diamond.