Kashmir sapphire origin determination: potential and limitations (2012)

GAHK$Seminar$23th$June$2012$

Kashmir sapphires: Potential and limitations of origin determination by chemical fingerprinting with LA ICP mass spectrometry Dr.$Michael$S.$Krzemnicki$&$P.$Halicki$ Swiss$Gemmological$Institute$SSEF$ $ Photos$©$M.S.$Krzemnicki,$SSEF,$except$where$indicated$otherwise$ The$data$presented$in$this$talk$are$the$part$of$the$Master$thesis$of$P.$Halicki,$University$Basel$and$SSEF$

Kashmir Sapphire

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11.01 ct SSEF Gemstone Report No. 63039 Sold for 10‘740‘000 HK$ at the Christies sale in HK in May 2012

© Swiss Gemmological Institute SSEF

Sapphires from Kashmir

© Swiss Gemmological Institute SSEF

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The velvety blue of Kashmir sapphires

Photos © H.A. Hänni, SSEF

Sapphires$from$Kashmir$contain$subQ microscopic$inclusions$which$scatter$the$ transmitted$light.$$ $ As$a$result,$these$stones$often$show$a$$ highly$appreciated$velvety$blue$colour.$ © Swiss Gemmological Institute SSEF

Treasured by the Maharadja

In$the$Padar$region$in$the$ Zanskar$mountain$range$$

The$Maharaja$of$Jammu$and$Kashmir,$circa$1900$ © Swiss Gemmological Institute SSEF www.kashmirphotos.org/history.html$

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The Kashmir sapphire mines

from$Tom$D.$LaTouche$(1890)$ Records(of(the(Geological(Survey(of(India.$

In$the$Padar$region$in$the$Zanskar$mountain$range:$ $ Q discovered$1880$ Q main$mining$operation$1882Q1887$ Q sporadic$activity$between$$1888$–$1945$and$up$to$nowadays,$but$no$evident$production$of$ gemQquality$material$anymore.$ © Swiss Gemmological Institute SSEF

Origin determination is always an expert opinion

The$origin$determination$of$gemmological$laboratories$is$always$based$on$scienti`ic$analyses$ (trace$element$composition,$absorption$spectra),$inclusion$analyses$(e.g.$Raman$ microspectrometry$and$FTIR$spectrometry)$and$meticulous$microscopic$observations.$ $

An$origin$of$a$gemstone$mentioned$on$a$gemstone$report$is$always$an$expert$opinion.$ © Swiss Gemmological Institute SSEF

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Coloured gemstones are formed during large-scale geological processes which have shaped the world as we know it today...!

Foto: Baltoro-Gletscher, Karakorum; Guilhem Vellut via, WikiCommons!

Kashmir sapphire Foto: Baltoro-Gletscher, Karakorum; Guilhem Vellut via, WikiCommons!

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The collision of the Indian plate with the Eurasian continental plate has produced some of the most important sources for coloured gems, such as the sapphires from Kashmir and the sapphires and rubies from Burma, and many more.!

Garnier et al. 2006!

Corundum in skarn!

Andranondambo!

1994"

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Sapphires from East-Africa, Sri Lanka, Madagascar, and South India Distribution$of$corundum$deposits$connected$to$ PanQAfrican$tectonoQmetamorphic$events$ (750Q450$ma)$by$the$collision$of$eastern$and$ western$Gondwana.$ $ In$midQJurassic$(about$160$ma),$India$started$to$ drift$towards$north.$

modi`ied$after$Collins$&$Windley$2002,$Santosh$&$Collins$2003)!

Economically important sapphire sources

Montana, USA Kashmir Burma (Myanmar)

Q Q Q Q Q Q Q Q Q

Kashmir-(India)Burma-(Myanmar)Ceylon-(Sri-Lanka)MadagascarTanzaniaPailin,-CambodiaAustraliaMontana-(USA)....-

Cambodia Ceylon (Sri Lanka) Tanzania

Madagascar Australia

© www.mygeo.info

© Swiss Gemmological Institute SSEF

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Origin determination: Combining$ classical$ approaches$ with$ advanced$ scienti`ic$ analytical$ methods$

© Swiss Gemmological Institute SSEF

Kashmir Sapphire

Lot$3798A$pair$of$sapphire$and$diamond$ ear$clips$by$Cartier$ 4.70$and$4.60$ct$ SSEF$report$62271$$$ © Swiss Gemmological Institute SSEF

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Pargasite$needles$(amphibole)$

© Swiss Gemmological Institute SSEF

Short-prismatic-tourmaline-

xenomorphous-plagioclase-

corroded-prismatic-zircon-

uraninite-with-tension-cracks-

Photos © H.A. Hänni, SSEF

© Swiss Gemmological Institute SSEF

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Photos © H.A. Hänni, SSEF

`ine$dust$tracks$

netQlike$healing$`issures$ © Swiss Gemmological Institute SSEF

CrQenriched$growth$layers$

Photo © H.A. Hänni, SSEF

© Swiss Gemmological Institute SSEF

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The Kashmir - Madagascar challenge !

The Kashmir - Madagascar challenge !

Photos © H.A. Hänni, SSEF

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Madagascar sapphire

Inclusion photos © H.A. Hänni, SSEF

Madagascar sapphire

Inclusion photos © H.A. Hänni, SSEF

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Madagascar sapphire

Inclusion photos © H.A. Hänni, SSEF

The Kashmir – Basaltic (e.g. Pailin) The blurred picture: Sapphire mix-up!

Overlapping$irregular$growth$ (heterogeneous$growth)$

Regular$growth$in$basaltic$sapphires$$ Photos: © Gemmological H.A. Hänni, SSEF © SSEF Swiss Institute

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Ceylon sapphire

Photos © H.A. Hänni, SSEF

© SSEF Swiss Gemmological Institute

UV-Vis Spectrometry

© SSEF Swiss Gemmological Institute"

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Raman microspectrometry

© Swiss Gemmological Institute SSEF

Laser Ablation Inductively Coupled Plasma Mass Spectrometry LA-ICP-MS

With Prof. Thomas Pettke ! at the Geochemical Lab, !

University of Berne, Switzerland!

© SSEF Swiss Gemmological Institute

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The LA-ICP-MS instrument The$instrument$at$the$Institute$of$ Geological$Sciences,$University$of$Berne$ (Switzerland)$has$been$optimized$for$ analyses$of$minerals$and$`luid$ inclusions$in$minerals.$

© Swiss Gemmological Institute SSEF

The LA-ICP-MS instrument

Microlas$system:$ Beam$modulation$optics$to$ homogenize$laser$beam$ energy$pro`ile$

Pettke, 2006!

Lambda$Physics,$Coherent:$ Pulsed$nanosecond$$ ArF$excimer$laser$(193$nm)$

Perkin$Elmer:$ DRCQe$quadrupole$mass$ spectrometer$

© Swiss Gemmological Institute SSEF

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Laser ablation

© T. Pettke,, University Berne

Local$heating$and$vaporization$

© Swiss Gemmological Institute SSEF

Important: Standardised Operation Procedures

Q Q Q Q Q

Laser$drill$holes$generally$60Q120$microns$(=0.06Q0.12$mm)$large$and$only$a$few$microns$deep.$ External$standardisation:$NIST$SRM$610$or$SRM$612$glass$standards$ Internal$standardisation$for$corundum$usually$99.5$wt%$Al2O3$ Carrier$gas$helium$admixed$with$hydrogen$for$better$ablation$yield$and$transport$ To$correct$for$any$possible$instrumental$drift,$each$analytical$series$starts$with$two$analyses$on$ the$multiQelement$standard$(SRM$610$or$612),$followed$by$maximum$16$analyses$on$the$ samples,$and$`inished$with$two$analyses$on$the$standard$again.$

$ $ © Swiss Gemmological Institute SSEF

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Features of LA ICP MS Chemical$analysis$of$specimens$

+$nearly$all$chemical$elements$can$be$analysed$ +$up$to$50$elements$at$the$same$time$ +$point$analysis$(zoning)$ +$only$minor$sample$preparation$ +$large$dynamic$range$of$analysis$$ $$$(from$subQppm$to$main$element$concentrations)$ +$quantitative$data$

Photo:$Aeschlimann,$2003$

Q$slightly$destructive$analysis$(laser$drill$holes$diameter$ca$100$µm)$ Q$how$representative$are$point$analyses$for$the$whole$stone?$ Q$raw$data$(qualitative)$has$to$be$processed$to$get$quantitative$data$ Q$contamination$effects$ Q$spike$`iltering$ Q$highly$sophisticated$instrument$$

© Swiss Gemmological Institute SSEF

Research study with LAICPMS on sapphires

Photo$©$P.$Halicki,$SSEF$

© Swiss Gemmological Institute SSEF

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Raw data Data processing homogeneous$signal$ LA-ICP-MS Pearls 100000000

Ca

counts

10000000

1000000

Mn

100000

Ba I Mg

10000

1000

Integration time

100

10 30

40

50

60

70

80

90

100

110

120

time (sec.)

Setting$of$integrals$for$data$processing$is$easy$ © Swiss Gemmological Institute SSEF

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Data processing

Surface$contamination$!$

Surface$contamination$!$

Spikes$!$

Spikes$!$

Spikes$!$

© Swiss Gemmological Institute SSEF

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Fe-(ppm)-

Results: Burma!

Madagascar!

Sri Lanka!

Kashmir!

Ti-(ppm)-

Fe-(ppm)-

Results:

Madagascar!

Kashmir!

Sri Lanka!

Ga-(ppm)-

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Ti-(ppm)-

Results:

Madagascar$

Madagascar!

Kashmir$

Burma$

Kashmir!

Burma!

Mg-(ppm)Thailand (Bo Phloi) + Cambodia

Possibilities & Limitations: Peucat et al (2007)

Comparison Comparison

Peucat$et$al.$2007$ 20.12.2011

80

20.12.2011

Peucat Peucatetetalal(2007) (2007)

24.04.2012 24.04.2012

75

Trace$element$ concentrations$ generally$indicate$ origin$„trends“,$but$ are$often$not$ resulting$in$ conclusive$results.$

Kashmir Kashmir this this study study

© Swiss Gemmological Institute SSEF

Zentraler ZentralerWeiterbildungskurs Weiterbildungskurs SGG SGG

30 30

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Conclusions:

Q LAQICPQMS$is$a$sophisticated$analytical$method$$ $$$$$$$to$characterise$the$chemical$composition$of$gemstones.$ $

Q

The$machine$produces$always$results,$but$are$they$real?$

$

Q $

Q

Many$instrumental$parameters$have$to$be$controlled$to$produce$reliable$ results.$ The$raw$data$has$to$be$carefully$processed$to$$avoid$any$artefact$or$ contamination.$

$

Q

For$sapphires,$large$overlapping$of$trace$element$concentration$ranges$occur.$

$

Q

Thus,$the$origin$determination$of$sapphires$cannot$rely$upon$only$trace$ element$analyses,$but$needs$the$important$contribution$$of$$spectral$and$ microscopic$evidences.$ © Swiss Gemmological Institute SSEF

A guide to the world s major sources of coloured gemstones, diamonds and pearls.! !

for more details see www.gemexplorer.org! also as a free App available in iTunes, ! © Swiss Gemmological Institute SSEF

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Thank you for your attention

© Swiss Gemmological Institute SSEF

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