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Spinel is a precious stone with a long history. In ancient societies spinel was considered to be an imitation of ruby. With the depletion of ruby mineral resources, gem—grade spinel has attracted more and more attention from consumers. In the last decade, as the popularity of spinel in the global colored gem market continues to rise, plenty of domestic and foreign jewelry brands have launched spinel based jewelry. This study takes spinels from Burma, Vietnam, Sri Lanka, and Tanzania as its research objects and performs a series of tests to obtain their gemological characteristics, spectral characteristics, and chemical composition, with the aim of comparing the differences between spinels with different colors from different areas and exploring the chromogenic mechanism of spinels. Only Burmese red spinels have a typical Cr spectrum. The types of inclusions and the contents of trace elements are the main differences between spinels from the four areas. Burmese spinel is characterized by an octahedral negative crystal filled with dolomite or a mixture of dolomite and calcite. Magnesite is present in Sri Lankan spinels, and dolomite is present in Tanzanian spinel. Dislocation systems and the presence of titanite and talc inclusions are strongly indicative features of Vietnamese spinel. Sri Lankan spinel is characterized by abundant gas–liquid inclusions, such as the beaded healing fissure. The trace element contents of the four areas are different. Burmese spinel is poor in Fe and Zn (Fe: 135.68–3925 ppm; Zn: 338.58–1312 ppm), while Burmese red spinel is rich in Cr (up to 7387 ppm). Vietnamese spinel is rich in Fe (3669.63–19,425 ppm) and poor in Ti content (<89 ppm), while Tanzanian spinel is rich in Zn (5129.96–7008 ppm). High content of Cr + V can lead to the red color in spinel, and the contents of Cr and V change obviously with color. Spinels appear red when Cr content is higher than V, while spinels appear orange when V content is higher than Cr. The red, pink, and orange spinels are colored by Cr3+ and V3+, showing a wide absorption band centered at 400 nm and 550 nm. Fe plays a dominant role in purple spinels. The purple spinel is colored by Fe3+ and Fe2+. [ABSTRACT FROM AUTHOR]

Recently found historical jewellery (Czech Republic) was subjected to detailed analyses to determine the gem inlays and the gold framework in which they are embedded. Such find fits into European jewellery archaeological artefacts containing similar stones from around the fifth century CE. The gemstones were analysed with optical microscopy and Raman micro-spectroscopy to determine their mineralogical characteristics and to find out typical structural-chemical differences based on which their provenance can be found. The results of this measurement discovered two main types of minerals from the garnet group, almandine and pyrope, where pyropes have been identified as Bohemian garnets thanks to the typical photoluminescence (PL) of chromium and vanadium impurities. The craftsmanship and processing of the goldsmith work were studied using X-ray computed tomography. Such a technique is an excellent contribution for detecting and visualising the internal parts hidden behind the placement of the stones. For this reason, 3D visualisation was used to describe and better understand all preserved parts. According to this object's very high cultural and historical value, the chosen methods are suitable for non-destructive study while proving to be essential to deepen our knowledge in archaeometric investigations focused on jewellery from Late Antiquity (with possible application to the jewellery from other periods). Based on the findings presented in this study, it is one of the world's oldest documented items using Bohemian garnets in jewellery. These findings underscore the tremendous economic and political importance of Bohemian garnet mineral resources altogether, with a second completely different type of garnet believed to have originated in distant India or Sri Lanka that was used in jewellery across Europe in Late Antiquity. [ABSTRACT FROM AUTHOR]

Entrepreneurial innovative action is a four-pronged strategic integration; it mitigates financial risk in knowledge transfer and technology transfer, it integrates manufacturing and business strategy, and it provides policy remedy to transform the assets and capabilities of the value system. The innovation process utilises market innovations to establish a competitive advantage, gathers intellectual assets, attains proprietary rights and fosters the ability to implement appropriate strategies and sustain a competitive advantage, thus generating premium value. The entrepreneur's commitment uncovers market opportunities and exploits the inventiveness of value-system technologies to result in market innovation. The integration of the above-mentioned four forces with changing market needs transforms the capabilities of the value system to allow it to sustain business value regeneration and thus generate premium value. The failure of either one or all four forces of entrepreneurs' innovative strategies will lead to a reduction in the market value of the products and disintegrate the industry value system. This phenomena was observed in the gem and jewelry industry in Sri Lanka, where the industry has been capable enough to develop a competitive product base but has been positioned to experience a reduction in market value. This reduction has resulted in the disintegration of the industry value system, forcing firms to work in isolation. [ABSTRACT FROM AUTHOR]