In late 2016, a new sapphire-producing mine was dis-covered at Bemainty, near Ambatondrazaka and Didy in Madagascar (Figure 5). The mine produced a consider-able amount of large sapphires, including Padparadascha and yellow sapphires (Figures 4a, c). The mining area has now been closed. The Bemainty mine lies north of the Didy mine (Figure 5) in a slightly different geological setting with-in a so-called Imorona-Itsindro Series.
The formation of sapphire at the Didy mine is believed to be related to Nb-Ta pegmatites that are mapped in the area south of Didy. Niobite inclusions found within sap-phires from Didy suggest a connection to these pegmatites (Peretti and Hahn, 2013). The geology of the new Bemain-ty mine and its surrounding does not indicate such Nb-Ta pegmatites, yet niobite inclusions in one of the samples from the new mine have been found. Currently fieldwork the area is not being undertaken due to elevated security risks (Figures 1a, b).
Spectacular inclusion features have been found in sap-phires from Bemainty and they resemble textbook Kash-mir (India) sapphire inclusions (Figures 6 to 11). As a con-sequence, a certain degree of misinterpretation of these sapphires seems to exist in the market, and a series of stones from Madagascar has possibly been falsely classi-fied as Kashmir sapphires (Krzemnicki 2013). Kashmir sap-phires have seen an unprecedented rise in value with pric-es that can reach well over $100,000 per carat, while their counterparts from Madagascar are ten times less expen-sive. This offers a great potential for fraud and the correct identification is thus an important part of the challenge of internationally recognized gem-testing laboratories.
In order to distinguish the sapphires from the new mine in Madagascar from those from Kashmir, we have prepared a Master Set of more than 50 reference samples from both mines, carefully selected to cover the entire range of inclu-sion features (Figures 4a, b, c).
The GRS Kashmir-Ambatondrazaka Master SetThe Kashmir Master Set of was prepared from the GRS
reference collection, comprised of hundreds of sapphire reference samples from Kashmir, collected over the last 20 years. Many of those samples have been cut in our own facility and then categorized according to different inclu-sions features, covering all the literature-published features of Kashmir sapphires.
The Ambatondrazaka Master Set includes samples that we received from two commissioned independent agents that we have sent to the new mines, as well as cut and pol-ished stones from more than five different reliable sources Figure 2. Countries with sapphire deposits of commercial importance. The Kashmir sapphire mine in northern India has been exhausted for decades and does not produce
Identification of sapphires from Madagascar with inclusion features resembling those of
sapphires from Kashmir (India)
Figures 1a, b. Mining in the Bemainty area near Ambatondrazaka in Madagascar before April 2017. Figure 1a shows a soil profile of theheavily weathered rocks containing sapphires. Fig. 1b gives an idea of the large crowd at this illegal mining site, with several tens of thousands of miners participating, leaving a trail of de-struction in the protected rainforest. (Photo is from the miner)
Dr. Adolf Peretti (FGG, FGA) and Francesca Peretti (GG)
significant amounts of sapphire besides isolated single find-ings. Madagascar is the major sapphire producer dominat-ing the world market supply. Madagascan sapphires are occasionally misrepresented as originating from Myanmar, Sri Lanka or Kashmir. InColor/ICA Figure 1a Figure 1b in the Bangkok market, all reported of being from the new depos-it. Among the samples are more than two dozen sapphires that contain typical Kashmir inclusions (e.g. Figure 6). These types of inclusions were found in rough samples that we obtained directly from the mine and kept as rough, Sizes range from 2 to 10 carats. Approximately 20% of our a very particular and unique way (Peretti et al, 1990). In the high Himalayas, pegmatites intruded into a series of amphibo-lite and ultramafic rocks (Figure 3b). During that process, the pegmatite was depleted of silica and a reaction rim of tourmaline was formed around the pegmatites (Peretti et al, 1990).
This process has become known as de-silification and it ultimately leads to the formation of sapphires within the pegmatites. The sapphires either formed within the peg-matite or in the reaction zone. There are different types of sapphires with varying inclusions such as tourmaline, pla-gioclase and amphibole, depending on the spot where the sapphire was formed.
Figure 1a Figure 1b
Figure 2. Countries with sapphire deposits of commercial impor-tance. The Kashmir sapphire mine in northern India has been exhausted for decades and does not produce significant amounts of sapphire besides isolated single findings. Madagascar is the major sapphire producer dominating the world market supply. Madagascan sapphires are occasionally misrepresented as origi-nating from Myanmar, Sri Lanka or Kashmir.
Figure 3b. The geology of the formation of Kashmir sapphire at this primary deposit. A pegmatite intrudes rocks of peridotite and amphibolite and produces a tourmaline reaction zone (Per-etti et al, 1990).
Below: Figure 3a. The Kashmir sapphire deposit is an isolated spot at an elevation of 4600 meters within the Himalayan moun-tain range. One of the authors (Adolf Peretti) studies the primary deposit at the site in the early 1990s. Only a few gemologists in the world made it to the Kashmir sapphire mine. (Photo: Rainer Kündig).
BELARUS
CENTRALAFRICAN REP.
EGYPT
SUDAN
ETHIOPIA
KENYA
LIBERIA
CÔTED'IVOIRE GABON
D.R. CONGO
ZAMBIAANGOLA
NAMIBIAZIMBABWE
BOTSWANA
SOUTHAFRICA
SENEGAL
GUINEABURKINA
FASO NIGERIA
MALI
ALGERIA
NIGERCHAD
SPAINPORTUGAL
POLAND
GAMBIA
SIERRA LEONE
RUSSIAN FEDERATION
MONGOLIA
CHINA
SAUDIARABIA
MALAYSIA
INDONESIA
CZECH REP. UKRAINEROMANIA
ITALY BULGARIA
GREECE TURKEYKYRGYZSTAN
IRANIRAQJORDAN KUWAIT
BAHRAIN
UNITED ARABEMIRATES
CYPRUSLEBANON
ISRAEL
QATARLIBYAN ARABJAMAHIRIYA
SYRIANARAB REP
CAMBODIA
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MOZAMBIQUE
TUNISIAMOROCCO
MAURITANIA
GHANABENIN
CAMEROONCONGO UGANDA
AUSTRIASWITZERLAND
BELGIUM
NETHERLANDSGERMANY
DENMARK
FRANCE
UNITED KINGDOM
SOMALIA
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LAO
THAILAND
WesternSahara
TAJIKISTAN
VIETNAM
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30 o
0 o
30 o
60 o
30 o
0 o
30 o
60 o
90 o
30 o 0 o 30 o 60 o 90 o
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MADAGASCAR
TANZANIA
AFGHANISTAN
BURMAMYANMAR
Jammu andKashmir
INDIA
PAKISTAN NEPAL
ultramafic rocks (enstatite-olivine)
Formation of Kashmir Sapphires
chromium-anthophyllite-tremolite
garnet-amphibolite
amphibolite
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nPKlsg
nPckGabbro
nPllebGabbro Otheoamphibolite (not assigned)
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Kiangara Series
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Imorona-Itsindro Series
Antananarivo Zone
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nPMPs
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nPMPz
Mananpotsy ComplexAntananarivo Zone
Plutonic rocks (and metamorphic equivalents)
Migmatic hornblende +_ biotitegarnet-orthoamphibolitenPllom
Hornblende-tonalite gneiss with± clinopyroxene and amphibolite boudins± garnet-bearing and pyroxene metadiorite;local charnockitisation
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Mafic granofels/mafic rocks with gabbro-likecompositionnAMMgtf
Betsiboka Series
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Beforona GroupTsaratanana Complex
Cr, deposit type not specified
Ni+/-Co, NIckel-bearing laterite
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Fe, deposit type not specified
Nb-Ta, columbite-tantalite bearing non-specified pegmatite
Ni, deposit type not specified
REE, Rare earth element deposit type not specifiedSn, deposit type not specified
Ni, lateritic nickel, nickel sulfide non-specified
Be, Beryl-bearing pegmatite
CunPlleb
EGP, Alluvial
Figure 4a. Parts of the GRS reference collection with sapphires from the new deposit near Bemainty in Madagascar
Figure 4b. the GRS Kashmir reference Master Set.
Below: Legend for Figure 5, opposite page.
Figure 4c. A selection of padparadscha sap-phires in a lot from the new mine in Mada-gascar for the GRS reference collection.
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Figure 5. Map showing the “Geology” for the Didy (Madagascar) mine. The Didy mine is situated in the metamor-phic rock suite of gneiss, amphibolite, quartzite, intercalated sillimaniteg-neiss (complex of Mananpotsy), migmatite garnet and biotite-bearing ortho-amphibolite. The Ambalavao rock suite surrounds the Didy mining area and contains quite different rock types including anatectic granites and migmatites. They are partially melted rocks typical for a lower high-meta-morphic continental crust. The new mine is located in the kiangara series (in the Legend, nPKLsg, with alcali granites and syenite rocks) bordering the Imorona-Istindro Series (in the Legend, NPllzg, with granites and gneisses).Legend edited and translated into English from French. Map cropped from Carte Métallogénique et de Prédiction des Gisements, Métaux de Base et Métaux Précieux, Feuille No 6, Toamasina (2008).
blue color zoning
v e r y f i n e streamers
w h i t e , c l o u d - l i k e inclusions, assorted with emerging smal l ru t i l e
irregular clouds of pin points over a wide area with isolated few rutile needles
streamer streamer
leathers
Figure 7. Sketch of the Madagascar sapphire inclusion details (Figure 6) revealing subtle differences to similar inclusions found in sapphires from Kashmir (Figures 15 and 17), e.g. development of small rutile needles around clouds. This phenomenon is absent in Kashmir sapphires.
Figure 8. Oscillating color zoning in a sapphire from the new mine in Madagascar. Note the occasional appearance of yellow color zoning. Such color zones have not been found in Kashmir sapphires of the GRS Master Set.
Figure 9. Fluid feathers containing yellow infillings. This is due to the late hydrothermal alteration and weathering process found in sapphires from Madagascar. This alteration within fluid inclusion feathers is absent in Kashmir sapphires. (Photo: Willy Bieri)
Figure 6. Inclusion features found in a high-value sapphire over 10 cts, originating from the new Bemainty sapphire mine in Mad-agascar as seen under 60x magnification and oblique fiber optic illumination. The minuscule details resembling clouds, streamers and striae, possess all the hallmarks of Kashmir sapphires. Only the study of minute details reveals differences (Figure 7). (Photo: Matthias Alessandri)
Figure 10. Clusters of long zircons included in the sapphires from Madagascar. The zircons have extensive tension cracks and are often corroded and milky. They are distinctly different from the zircon inclusions found in Kashmir sapphires (Figure 16).
Figure 11. Oscillating milky and blue zones and streamers perpendicular to the growth zones are found in this gemquality cornflower blue sapphire from the new mine in Madagascar (viewed under fiber optic illumination). At first glance, it resem-bles the inclusion features of a Kashmir sapphire. Only the study of minor details allows a distinction from features observed as inclusions in Kashmir sapphires.
Figure 12a. Two examples of Kashmir sapphires that are part of the GRS Kashmir reference Master Set. On the left is a crosssection through a 20-ct gem-quality Kashmir sapphire with a polished window. On the right is a 100+ ct Kashmir sapphire carving by Glenn Lehrer, California. The carved Kashmir contains a 5-mm dravite tourmaline over-growth, proving its Kashmiri origin. All the samples were obtained before the opening of the new deposit in Mad-agascar.
Figure 12b. The same two Kashmir sap-phires as in Figure 12a are exposed to long-wave ultraviolet light and exhibit
distinctive fluorescence. Left: Core of a Kashmir sapphire shows yellow-orange
fluorescence, followed by a zone of inert reaction to UV-light and an outer rim of red
fluorescence. Right: The Kashmir sapphire shows red fluorescence throughout its
body and possesses a distinctive zone of intense red fluorescence, restricted to a
growth zone within the crystal. Yellow fluo-rescence was exclusively found in Kashmir sapphires, while red fluorescence can also
be observed in sapphires from the new deposit in Madagascar.
Figure 15
Figure 16
Figure 13
Figure 17
Figure 18
Figure 14
Implications for the MarketThe surfacing of new gemstone deposits is proving to
be a serious challenge for gemological laboratories. A solution to this problem is to have a reference collection that has been established over a period of more than 20 years. It took us some time to collect the different types of Kashmir sapphires with different inclusion properties. Only two to three Kashmir sapphire samples per year could be purchased from reliable sources between 1994 and 2015.
Finding reference samples of the new mine from Mad-agascar was especially difficult, since traders did not co-operate in selling samples to the laboratory, particularly those with Kashmir-like inclusion features. It was necessary for us to get the samples in 2016 anonymously, pretending to be serious buyers through agents and paying high mar-ket prices.
Based on our Master Sets, we can confirm that com-paring the minute details of the sapphires makes it possi-ble to distinguish the two different origins. Re-checking is recommended for sapphires in the market between 2016 and 2017, which are claimed to be from Kashmir.
Warning About Potential Origin-Misinterpreta-tion of Padparadscha Sapphires from the Be-mainty Deposit
Remarkably large and beautiful padparadscha sap-phires have been found in this new deposit with sizes that can exceed 20 carats. We came across cases where they have been misinterpreted in the trade as originating from Sri Lanka.
The padparadscha from Bemainty can be identified based on their characteristic color zoning (Figure 19) in combination with their distinctive FTIR spectrum (Figure 20). The FTIR spectrum though is not exclusive to this origin.
We have encountered situations where clients con-firmed a padparadscha’s origin as from this new depos-it in Madagascar, but declined to accept our gemstone report since the stone came with other gemstone reports stating a Sri Lankan origin ass the most probable prove-nance. This requires a “Trade Alert” to the public in addi-tion to the that previously published about the new Kash-mir-like sapphires from Madagascar
Preliminary Comparison StudyWe have compared the following properties of the
samples for this preliminary report:
A) Solid inclusionsB) Fluid inclusionsC) Age of zircon inclusionsD) Color zoningE) Inclusion features indicative of Kashmir sapphiresF) UV-fluorescence analysis
Further analysis is currently focused on oxygen iso-topes, zircon ages, LA-ICP-MS analysis and SEM-EDS. We will report further on our findings in the near future. For the first report, we focused on sapphires that are potentially at risk for being mixed up with Kashmir sapphires. We have found the following results.
A) Zircon habit: both origins may contain long zircon crystals (Figures 10, 16). They can, however, be easily dis-tinguished from each other. Uraninite crystals are only present in Kashmir sapphires. Tourmaline inclusions of dra-vite compositions are exclusive to Kashmir sapphires as of now (Figure 14).
B) Kashmir sapphires contain a special type of pseudo secondary fluid inclusion features. These types of inclu-sions are largely absent in our master stones from the new deposit in Madagascar (Figure 15).
C) Isolated yellow color zones were found in samples from the new mine in Madagascar (Figure 8). These yellow color zones are not present in Kashmir sapphires.
D) The age of Kashmir sapphire zircons was found to be 23 million years old. The sapphires from the new deposit in Madagascar are older than 200 million years as can be concluded from the geological set-up of the rock forma-tions. This can be established using LA-ICP-MS analysis.
E) Al-hydroxide inclusion features, often referred to as Kashmir-type inclusions, show small differences. These differences can be seen, if the inclusion features are sketched and analyzed in detail (example Figure 7).
F) Fluorescence analysis has shown that UV-fluores-cence criteria reported earlier (Krzemnicki 2013) cannot be applied (Figures 12a, b).
Figure 13. An amphibole inclusion in a Kashmir sapphire is accompanied by a fluid inclusion feather. The singly isolated fluid inclusion voids are arranged in a distinct flat area. When illuminated with an oblique fiber optic light, the fluid inclusion tubes reflect simultane-ously. This type of fluid incisions is typically found in Kashmir sapphires.Figure 14. Opaque cubic inclusions found in Kashmir sapphires, identified as uraninite. They are generally absent in sapphires from the new deposit in Madagascar, but can be found in sapphires from Adranondambo in southern Madagascar (Gübelin and Peretti, 1997, 1998). For the purpose of distinguishing sapphires from Kashmir from sapphires from the new deposit in Madagascar, these crystals are helpful, although not always present, but serve as an important distinction criteria.Figures 15 and 17. Clouds of Al-hydroxide are often found in gem-quality Kashmir sapphires. These inclusions were generally believed to be exclusive to Kashmir sapphires until the arrival of sapphires from the new sapphire mines in Madagascar.Figure 16. A cluster of long needle-shaped zircons without any tension cracks, found in a sapphire from Kashmir. The inventory of zir-con habits is relatively complex and includes various types of different zircon inclusions. Comparing zircon habits, corrosion features, growth zoning inside the zircons and geometry of the tension cracks around zircons provides a key feature for distinguishing the Mad-agascan sapphires from their Kashmir counterparts.Figure 18. Dravite inclusions in a sapphire from Kashmir are still considered a strong indication for their origin (see their occurrence at the primary deposit, Figure 3b). Further inclusion analysis in sapphire from the new deposit is currently underway to test this argu-ment.
References
1) E.J. Gübelin and Adolf Peretti, 1997. Sapphires from the Adranondambo mine in SE Madagascar: evidence for metasomatic skarn formation. Journal of Gemology, 25,7, pp. 453-516.
2) E.J. Gübelin and Adolf Peretti, 1998. Die Saphire von Adranondambo Eine neue Lagerstätte auf Madagascar. NZZ Neue Zürcher Zeitung, Forschung und Technik, Nr. 86, page 65.
3) Krzemnicki, M.S., 2017. ‘Kashmir-like’ sapphires from Madagascar entering the gem trade in large sizes and quantities. SSEF Trade Alert, [Online]. Available at: http://www.ssef.ch/fileadmin/Documents/PDF/SSEF_TRADE_ALERT_-Kashmir-like__sapphires_from_Madagascar__en-tering_the_gemtrade_in_large_sizes_and.pdf [Accessed 22 May 2017].
4) Pardieu, V., Vertriest, W., Weeramonkhonlert, V., Ray-naud, V., Atikarnsakul, U., Perkins, R., A, 2017. Sapphires from the gem rush Bemainty area, Ambatondrazaka (Madagascar). GIA Bangkok News from Research, [On-line]. 1-45. Available at: https://www.gia.edu/gia-news-research/sapphires-gem-rush-bemainty-ambatondraza-ka-madagascar [Accessed 22 May 2017].
5) Peretti, A., 2008. Winza ruby identified. Contributions to Gemology, No. 7, page 90 (available at www.gemre-search. ch)
6) Peretti, A., Hahn, L., 2013. Record-breaking Discovery ofRuby and Sapphire at the Didy Mine in Madagascar: In-vestigating the Source. GRS - Contributions to Gemology, 13, 2-15.
Fig. 20 FTIR-transmission spectra of an unheated Padparadscha sapphire from the new mine in Madagascar (Bemainty, Ambatondrazaka). Note the prominent line at 3160 cm-1. Similar spectra were described for rubies from Winza, Tanzania (Peretti 2008).
Figure 19. Microphotograph taken of the interior structure of a padparadscha sapphire (over 20 cts in size) from the new mine in Madagascar. Pink, yellow and orange color zoning is revealed with occasional isolated blue zones that are not shown in this picture (40x microscope magnification using transmitted light). These features, in combination with the infrared spectrum (Figure 20) as well as additional chemical and spectroscopic data, are characteristic of padparadscha sapphires from this new deposit. This allows the determination of the origin of this new type of padparadscha sapphire from the Bemainty deposit near Ambatondrazaka.
7000 6000 5000 4000 3000 2000 1000cm-1
%T
3160 cm-1
7) Peretti, A., J. Mullis and R. Kündig, 1990. Die Kaschmir-Sa-phire und ihr geologisches Erinnerungsvermögen. NZZ Neue Zürcher Zeitung. Forschung und Technik, 15.August, Nr. 187, page 59.8) Peretti, A. et al., 2017. Gems from Mogok (including spi-nel) and Kashmir and identification against their natural counterparts, textbook with 558 pages, more than 900 fig-ures (release September 2017, Hong Kong Jewellery and Gem Fair, GRS Seminar).
9) Carte Métallogénique et de Prédiction des Gisements, Métaux de Base et Métaux Précieux, Feuille No 6-Toama-sina (2008) (J. Ramarolahy, D. Rakotomanana, B. Moine, E.Ortega, L. Chevallier, F. Hartzer, G. S. de Kock, S. W. Strausset, A. F. Randriamanantenasoa, J. Naden, L. Noakes, Editée par: British Geological Survey Keyworth, Notting-ham, UK) MINISTÈRE DE L’ÉNERGIE ET DES MINES Projet de Gouvernance des Ressources Minérales (PGRM).
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