Figure 8 - uploaded by Gérard Panczer
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A: Detail of the natural, uncut surface on the Grand Sapphire. B: A doubly terminated gem sapphire monocrystal from the Monaragala district, Sri Lanka (45 × 11 × 12 mm; MNHN inventory number 195.146). C: Detail of the Sri Lankan sapphire's surface, showing crystal growth terraces. D: Two "opposite" views of the Grand Sapphire examined under a polariscope and oriented slightly off the c-axis (shown in dark blue). E: Three-dimensional reconstruction showing the probable location of the Grand Sapphire within a hypothetical trigonal/hexagonal corundum crystal. Photos by François Farges, © MNHN.
Source publication
Since it was added to the French crown jewels in 1669, the 135.74 ct Grand Sapphire has been regarded as one of the world's most magnificent sapphires. Newly discovered archives indicate that Louis XIV obtained the Grand Sapphire at about the same time he acquired the Tavernier Blue diamond; both gems were mounted in gold settings in 1672. Although...
Citations
... In addition, the lack of the absorption band at 880 nm, assigned to Fe 2+ , is usually taken as a clue for the metamorphic origin of the gemstone, rather than basalt-related [15,16], which would include Madagascar, Sri Lanka and Vietnam as possible geographic sources. Considering that the only active deposits in the Middle Ages were in Myanmar, Sri Lanka, and Thailand-Cambodia [17], an origin from south-eastern Asia is highly probable. The Greek writer, traveller and merchant Cosmas Indicopleustes, in his 6th century Christian Topography [18] cited the island of Taprobane, modern Sri Lanka, as the source of "hyacinth stone", interpreted as sapphire or as amethyst. ...
The Desana treasure is a remarkable assemblage of items made of gold, silver, gemstones and glasses found in north-western Italy. Most scholars agree on the fact that the core of the treasure might have belonged to a single deposit resulted from a long period of selection, accumulation and use. The treasure testifies to the evolution of goldsmiths’ art in Ostrogothic Italy and represents an extraordinary material trace of the Italian elites of the 5th–6th centuries. The Desana treasure was investigated with non-invasive instrumental analytical techniques, namely optical microscopy, UV-visible diffuse reflectance spectrophotometry with optical fibres and X-ray fluorescence spectrometry in order to record the chemical features of gemstones, coloured glasses and precious metals employed to produce the items. As for the gemstones, besides identifying typologies, data suggested India as the source for a sapphire pendant and for most of the garnets, whereas the emeralds may belong to different sources, among which Pakistan, India and Egypt. The investigation revealed the colouring agents and compositional features of the glasses, and the composition of the gold alloys. The results of the investigation highlight that the raw materials used by Late Antique Italian goldsmiths did not differ significantly from other neighbouring European and Mediterranean regions, although the garnets show some differences if compared with coeval jewels recorded north of the Alps. The dataset produced in this work complements the stylistic approach for the study of these amazing traces of the past and deepens our knowledge on the role of the Italian “Ostrogothic” jewellery in the frame of the coeval Mediterranean, Central European and Northern Pontic metalwork traditions.
... However, over the past decade the development of portable and compact spectroscopic equipment has made on-site analysis possible for historical jewels, avoiding the need to transport these delicate objects to laboratories (e.g. Reiche et al. 2004;Farges et al. 2015;Panczer et al. 2019). The resulting analyses are not as complete as those that could be obtained in a laboratory or on unset stones, but by combining the instrument data with historical information it is sometimes possible to propose geographical origins for the gems. ...
... This study shows the value of portable Raman spectroscopy for identifying set gemstones and previously misidentified (or imitation) gems in historical jewels, as also demonstrated for the 11th-century Heinrich's Cross reliquary from the treasury of Basel cathedral (Reiche et al. 2004), the 13th-century head reliquary of St Eustace from the same treasury (Joyner et al. 2006), the 13th-century Chiaravalle Cross (Di Martino et al. 2019) and an 18th-century Slovenian baroque chalice (Jeršek & Kramar 2014). The on-site collection of Raman data in combination with portable EDXRF spectroscopy further enabled confident determination of the provenance of certain gemstones in the 9th-century Talisman of Charlemagne reliquary (Panczer et al. 2019) and the 17th-century Grand Sapphire of Louis XIV (Farges et al. 2015). ...
The book of hours examined for this study is an illuminated Renaissance masterpiece: a small prayer book bound in enamelled gold and gemstones that was bought in 1538 by King Francis I of France as a probable gift for his niece. In 2018, it was acquired by the Louvre Museum (Paris, France) from S. J. Phillips Ltd in London, and its nearly complete history is documented here.
A first gemmological analysis of the stones adorning the book was conducted on site at the Louvre in 2020. The gems consist of carnelian (two intaglios and eight cameos), rubies (27 polished pieces),
turquoise (24 cabochons) and rhodolite (one faceted stone in the book’s clasp that has been described as tourmaline since 1942). We suggest that most of the rubies were mined from the Mogok area of
Burma (now Myanmar). Based on historical considerations, the turquoise could have originated from Persia or possibly Uzbekistan, and the carnelian from either India or Saxony. The faceted rhodolite
could have originated from India or Sri Lanka, and was most likely added to the clasp in more recent times, possibly between 1842 and 1884.
... The sample K-06 (white spodumene) due to the very low concentration of chromophores, did not show any significant absorbance in the visible region as depicted in Figure 6; there was only a little absorption at 376 nm and 480 nm. All the samples (K-01 to K-05) showed very weak absorption bands in the ultraviolet region at 376 nm and in the visible region between 400 to 500 nm (410, 440, 450 and 480 nm), the absorption is due to Fe 3+ [25,26], in Figure 7 only one spectrum is represented for explanation. There was a strong absorption band at 530 nm and the absorbance was intense along c-axis as compared to another optical axes. ...
... The sample K-06 (white spodumene) due to the very low concentration of chromophore, did not show any significant absorbance in the visible region as depicted in Figure 6; there was only a little absorption at 376 nm and 480 nm. All the samples (K-01 to K-05) showed very weak absorption bands in the ultraviolet region at 376 nm and in the visible region between 400 to 500 nm (410, 440, 450 and 480 nm), the absorption is due to Fe 3+ [25,26], in Figure 7 only one spectrum is represented for explanation. There was a strong absorption band at 530 nm and the absorbance was intense along caxis as compared to another optical axes. ...
Kunzite, the pink variety of spodumene is famous and desirable among gemstone lovers. Due to its tenebrescent properties, kunzite always remains a hot research candidate among physicists and mineralogists. The present work is continuing the effort towards value addition to kunzite by enhancing its color using different treatments. Before color enhancement, it is essential to identify the chromophores and their oxidation states. In this paper, the authors investigated the main impurities in natural kunzite from the Nuristan area in Afghanistan and their valence states. Some impurities in the LiAlSi2O6 spodumene structure were identified and quantified by using sensitive techniques, including Laser Ablation Inductively Coupled Plasma Mass Spectrometry (LA-ICP-MS), UV−VIS and X-ray absorption near-edge structure (XANES). LA-ICP-MS indicated many trace elements as impurities in kunzite, among which Fe and Mn are the main elements responsible for coloration. The oxidation states of these two transition elements were determined by the XANES technique. The study reveals that Mn is present in both Mn2+ and Mn3+ oxidation states, while Fe is present only in Fe3+ oxidation state.
... It is only rather recently that items of historical jewelry have been analyzed on-site using spectroscopic methods that are portable and compact (Häberli, 2010;Barone et al., 2014;Jeršek and Kramar, 2014;Reiche et al., 2014;Farges et al., 2015). Often these are the only analytical methods possible when cultural treasures cannot be moved from their location, such as a museum or historical site. ...
... To our knowledge, the center sapphire of the Talisman of Charlemagne is the largest sapphire used in European jewelry during the Early to High Medieval period. For comparison, the historic Grand Sapphire of Louis XIV weighs 135 ct or 27 grams (Farges et al., 2015). ...
... The sapphires are perfectly monocrystalline, between two cross polarizer the crystals didn't present any mark of defect (see figure 2) [21] [22] . The scattering area cannot be explained by crystal twinning, grain boundary or any crystalline disorientation. ...
Rare minerals – and more particularly gems – were the preferred instruments of power for past rulers. In the 19th century, these political objects became scientific: gemology was born as a branch of mineralogy. Unpublished archives also allow us to better understand the often tormented past of these gems and their presence in the French National Museum of Natural History. In the 17th century, Louis XIV took possession of two of the most beautiful blue gems known at the time: the Grand Diamant Bleu (Great Blue Diamond) and the Grand Saphir (Grand Sapphire). Considerable ab initio calculations of the color of the Hope diamond were undertaken to elucidate the anomaly. For this purpose, the theoretical dielectric function of a diamond was calculated by considering a doping of its cubic atomic structure with boron atoms, present in trace amounts in the carbon atomic structure of this mineral and supposedly the source of its blue color.
In this study, zircon inclusions in selected 115 unheated sapphires originating from metamorphic deposits were studied by confocal micro‐Raman spectroscopy. By comparing Raman features of zircon inclusions in gem‐quality sapphires from Myanmar, India (Kashmir), Sri Lanka, and Madagascar, it could be established that those of younger age (sapphires from Myanmar and India [Kashmir]) contain zircon inclusion which exhibit relatively low ʋ1 and ʋ3 band positions and also smaller FWHM (ʋ3) than those in the older sapphires from Sri Lanka and Madagascar. Binary plotting of ʋ1 versus ʋ3 frequencies (Figure 3) and ʋ3 wavenumber versus FWHM of the studied zircon inclusions provide a method to distinguish young sapphires formed during Alpine‐Himalayan orogeny (Kashmir, Myanmar) from those related to the Pan‐African orogeny (Sri Lanka, Madagascar). This study shows the potential of the non‐destructive method on zircon inclusions in sapphires to be used to distinguish their origin as a service to the commercial gem trade. Zircon inclusions in selected 115 unheated sapphires originating from metamorphic deposits—Myanmar, India (Kashmir), Sri Lanka, and Madagascar—were studied by confocal micro‐Raman spectroscopy. This study shows the potential of the non‐destructive method on zircon inclusions in sapphires to be used to distinguish their origin as a service to the commercial gem trade.
The Kyropoulos technique allows growing large diameter Ti-doped sapphire for Chirped Pulse Amplification CPA laser. A scattering defect particular to Kyropoulos grown crystal is presented. This defect is characterized by different techniques: luminescence, absorption measurement, X-ray rocking curve, Transmission electron microscopy measurements. The impact of this defect to the potential application in CPA laser is evaluated. The nature of this defect is discussed. Modified convexity of the interface is proposed to avoid the formation of this defect and increase the quality of the Ti-doped sapphire crystal.
