Identification of sapphires from Madagascar with inclusion features resembling those of sapphires from Kashmir (India) Dr. Adolf Peretti (FGG, FGA) and Francesca Peretti (GG) 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 Figure 1a Figure 1b from the new mine have been found. Currently fieldwork Figures 1a, b. Mining in the Bemainty area near Ambatondrazaka the area is not being undertaken due to elevated security in Madagascar before April 2017. Figure 1a shows a soil profile risks (Figures 1a, b). Spectacular inclusion features have been found in sap- of theheavily weathered rocks containing sapphires. Fig. 1b gives phires from Bemainty and they resemble textbook Kash- an idea of the large crowd at this illegal mining site, with several mir (India) sapphire inclusions (Figures 6 to 11). As a con- tens of thousands of miners participating, leaving a trail of de- sequence, a certain degree of misinterpretation of these struction in the protected rainforest. (Photo is from the miner) 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 significant amounts of sapphire besides isolated single find- identification is thus an important part of the challenge of ings. Madagascar is the major sapphire producer dominat- internationally recognized gem-testing laboratories. ing the world market supply. Madagascan sapphires are In order to distinguish the sapphires from the new mine in occasionally misrepresented as originating from Myanmar, Madagascar from those from Kashmir, we have prepared Sri Lanka or Kashmir. InColor/ICA Figure 1a Figure 1b in the a Master Set of more than 50 reference samples from both Bangkok market, all reported of being from the new depos- mines, carefully selected to cover the entire range of inclu- it. Among the samples are more than two dozen sapphires sion features (Figures 4a, b, c). that contain typical Kashmir inclusions (e.g. Figure 6). These types of inclusions were found in rough samples that we The GRS Kashmir-Ambatondrazaka Master Set obtained directly from the mine and kept as rough, Sizes The Kashmir Master Set of was prepared from the GRS range from 2 to 10 carats. Approximately 20% of our a very reference collection, comprised of hundreds of sapphire particular and unique way (Peretti et al, 1990). In the high reference samples from Kashmir, collected over the last 20 Himalayas, pegmatites intruded into a series of amphibo- years. Many of those samples have been cut in our own lite and ultramafic rocks (Figure 3b). During that process, facility and then categorized according to different inclu- the pegmatite was depleted of silica and a reaction rim sions features, covering all the literature-published features of tourmaline was formed around the pegmatites (Peretti of Kashmir sapphires. et al, 1990). The Ambatondrazaka Master Set includes samples that This process has become known as de-silification and we received from two commissioned independent agents it ultimately leads to the formation of sapphires within the that we have sent to the new mines, as well as cut and pol- pegmatites. The sapphires either formed within the peg- ished stones from more than five different reliable sources matite or in the reaction zone. There are different types of Figure 2. Countries with sapphire deposits of commercial sapphires with varying inclusions such as tourmaline, pla- importance. The Kashmir sapphire mine in northern India gioclase and amphibole, depending on the spot where has been exhausted for decades and does not produce the sapphire was formed. o o o o o o 30 0 30 60 90 o 60 UNITED 60 KINGDOM DENMARK RUSSIAN FEDERATION NETHERLANDS BELARUS GERMANY POLAND BELGIUM CZEC. H REP UKRAINE AUSTRIA MONGOLIA FRANCESWITZERLAND ROMANIA ITALY BULGARIA KYRGYZSTAN Figure 2. Countries with sapphire deposits of commercial impor- PORTUGAL SPAIN GREECE TURKEY tance. The Kashmir sapphire mine in northern India has been SYRIAN TAJIKISTAN TUNISIA CYPRUS Jammu and exhausted for decades and does not produce significant amounts ARAB REP IRAN AFGHANISTAN Kashmir CHINA MOROCCO LEBANON IRAQ of sapphire besides isolated single findings. Madagascar is the o ISRAEL JORDAN o KUWAIT PAKISTAN 30 ALGERIA LIBYAN ARAB NEPAL major30 sapphire producer dominating the world market supply. Western BAHRAIN JAMAHIRIYA EGYPT QATAR Sahara SAUDI VIETNAMadagascanM sapphires are occasionally misrepresented as origi- ARABIA UNITED ARAB INDIA EMIRATES nating from Myanmar, Sri Lanka or Kashmir. MAURITANIA LAO OMAN MALI NIGER BURMA SENEGAL CHAD YEMEN THAILAND BURKINA SUDAN MYANMAR GAMBIA FASO CAMBODIA Formation of Kashmir Sapphires GUINEA BENINNIGERIA SIERRA LEONE GHANA CENTRAL ETHIOPIA 1 1 ultramafic rocks (enstatite-olivine) LIBERIA AFRICAN R.EP 2 3 4 MALAYSIA 2 chromium-anthophyllite-tremolite CAMEROON SOMALIA SRI LANKA UGANDA SINGAPORE o CÔTE CONGO o 3 garnet-amphibolite 0 D'IVOIRE GABON KENYA 0 4 amphibolite D.R. CONGO INDONESIA 5a 5b 6 5 alteration zone TANZANIA a) talc-cabonate b) biotite ANGOLA 6 contact zone, tourmaline rim ZAMBIA 7b (dravite, schorl) corundum-plagioclase-pegmatite ZIMBABWE 1 7 a) unaltered rock NAMIBIA MOZAMBIQUE b) partially prelaced into BOTSWANA MADAGASCAR fine-grained mica, kaolinite and carbonate corundum (colorless) or o SOUTH o 7a sapphire (light blue or blue) 30 AFRICA 30 1 m Below: Figure 3a. The Kashmir sapphire deposit is an isolated Figure 3b. The geology of the formation of Kashmir sapphire at spot at an elevation of 4600 meters within the Himalayan moun- this primary deposit. A pegmatite intrudes rocks of peridotite tain range. One of the authors (Adolf Peretti) studies the primary and amphibolite and produces a tourmaline reaction zone (Per- 30 o 0 o deposit30 o at the site in the early60 o1990s. Only a few gemologists90 o in etti et al, 1990). the world made it to the Kashmir sapphire mine. (Photo: Rainer Kündig). 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. Figure 4c. A selection of padparadscha sap- phires in a lot from the new mine in Mada- gascar for the GRS reference collection. Below: Legend for Figure 5, opposite page. Legend Sedimentary and Volcanic Rocks (and metamorphic equivalents) Plutonic rocks (and metamorphic equivalents) Non-specified alluvial rocks Tsaratanana Complex Antananarivo Zone Betsimisaraka Zone Qa Beforona Group Ambalavao Series Imorona-Itsindro Series Betsimisaraka Zone Migmatic plagioclase gneiss with biotite Anatectic granite, idiomorphic Migmatic hornblende +_ biotite Mananpotsy Complex nATAfo ± hornblende and granitogneiss with ЄAgro K-felspar Facies nPllom garnet-orthoamphibolite amphibolite lenses and porphyroblastic Anatectic granite/migmatized, Formation of Sakanila gneiss nPMPs Biotite-Gneiss ± hornblende and ЄAgr not differentiated Betsiboka Series amphibolite with quartzite unites/ Mafic biotite gneiss mafique, banded and nATAfz quarzite lenses, graphite lenses locally sheared, with quartzite, amphibole Hornblende-tonalite gneiss with ± sillimanite ± garnet rocks and and pyroxene, metagabbro and Kiangara Series nAMMgt ± clinopyroxene and amphibolite boudins nPMPss meta-ultramafitite some calcsilicate marbles Alkali granite and syenite gneiss, ± garnet-bearing and pyroxene metadiorite; Gneiss à sillimanite Amphibole-gneiss nPKlsg polyphase stratified, coarse-grained local charnockitisation nATAfzag and medium differentiated (biotite Antananarivo Zone syenogranite, alcaline-leucogranite Mafic granofels/mafic rocks with gabbro-like nAMMgtf composition Mananpotsy Complex and quartz-bearing syenite). Ambatondrazaka Formation Cr, deposit type not specified nPMPz Biotite-Gneiss (± sillimanite Fe, deposit type not specified Imorona-Itsindro Series ± graphite) with lenses of quartzite Ni, deposit type not specified Granite charnocktic granites or Granite with biotite or hornblende and and amphibolite nPck charnockites (not assigned) nPllzg intercalated layers of older gneiss rocks. EGP, Alluvial REE, Rare earth element Gabbro deposit type not specified nPlleb Cu Sn, deposit type not specified Gabbro Otheoamphibolite (not assigned) Large deposit nPlleb Ni, lateritic nickel, nickel sulfide non-specified Nb-Ta, columbite-tantalite bearing nPlleam non-specified pegmatite Be, Beryl-bearing pegmatite Ni+/-Co, NIckel-bearing laterite � � D � � � � � �� �� � � � � � � � � � � � � � � M � � � D � !( � � � � �� !(� � � � !(<!(� � � � O � � � � �