HK June 2012 Kashmir sapphire - SSEF
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Transcript of HK June 2012 Kashmir sapphire - SSEF
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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$$Photos$©$M.S.$Krzemnicki,$SSEF,$except$where$indicated$otherwise$The$data$presented$in$this$talk$are$the$part$of$the$Master$thesis$of$P.$Halicki,$University$Basel$and$SSEF$
GAHK$Seminar$23th$June$2012$
Kashmir Sapphire
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© Swiss Gemmological Institute SSEF
11.01 ct SSEF Gemstone Report No. 63039 Sold for 10‘740‘000 HK$ at the Christies sale in HK in May 2012
Sapphires from Kashmir
© Swiss Gemmological Institute SSEF
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The velvety blue of Kashmir sapphires
Sapphires$from$Kashmir$contain$subQmicroscopic$inclusions$which$scatter$the$transmitted$light.$$$As$a$result,$these$stones$often$show$a$$highly$appreciated$velvety$blue$colour.$
Photos © H.A. Hänni, SSEF
© Swiss Gemmological Institute SSEF
© Swiss Gemmological Institute SSEF
In$the$Padar$region$in$the$Zanskar$mountain$range$$
Treasured by the Maharadja
The$Maharaja$of$Jammu$and$Kashmir,$circa$1900$www.kashmirphotos.org/history.html$
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© Swiss Gemmological Institute SSEF
from$Tom$D.$LaTouche$(1890)$Records(of(the(Geological(Survey(of(India.$
The Kashmir sapphire mines
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.$
Origin determination is always an expert opinion
© Swiss Gemmological Institute SSEF
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.$$
An$origin$of$a$gemstone$mentioned$on$a$gemstone$report$is$always$an$expert$opinion.$
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Foto: Baltoro-Gletscher, Karakorum; Guilhem Vellut via, WikiCommons!
Coloured gemstones are formed during large-scale geological processes which have shaped the world as we know it today...!
Kashmir sapphire Foto: Baltoro-Gletscher, Karakorum; Guilhem Vellut via, WikiCommons!
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The collision of the Indian plate with the Eurasian continental plate has produced some of the most important sources for coloured gems, such as the sapphires from Kashmir and the sapphires and rubies from Burma, and many more.!
Garnier et al. 2006!
Corundum in skarn!Andranondambo !
1994"
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Sapphires from East-Africa, Sri Lanka, Madagascar, and South India
Distribution$of$corundum$deposits$connected$to$PanQAfrican$tectonoQmetamorphic$events$(750Q450$ma)$by$the$collision$of$eastern$and$western$Gondwana.$$In$midQJurassic$(about$160$ma),$India$started$to$drift$towards$north.$
modi`ied$after$Collins$&$Windley$2002,$Santosh$&$Collins$2003)!
© Swiss Gemmological Institute SSEF
Tanzania
Australia
Kashmir
Burma (Myanmar)
Cambodia
Montana, USA
Ceylon (Sri Lanka)
Madagascar
© www.mygeo.info
Q Kashmir-(India)-Q Burma-(Myanmar)-Q Ceylon-(Sri-Lanka)-Q Madagascar-Q Tanzania-Q Pailin,-Cambodia-Q Australia-Q Montana-(USA)-Q ....-
Economically important sapphire sources
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© Swiss Gemmological Institute SSEF
Origin determination:
Combining$classical$approaches$with$advanced$scienti`ic$analytical$methods$
Lot$3798-A$pair$of$sapphire$and$diamond$ear$clips$by$Cartier$4.70$and$4.60$ct$SSEF$report$62271$$$
© Swiss Gemmological Institute SSEF
Kashmir Sapphire
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Pargasite$needles$(amphibole)$
© Swiss Gemmological Institute SSEF
© Swiss Gemmological Institute SSEF
xenomorphous-plagioclase- Short-prismatic-tourmaline-
corroded-prismatic-zircon- uraninite-with-tension-cracks-Photos © H.A. Hänni, SSEF
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© Swiss Gemmological Institute SSEF
`ine$dust$tracks$
netQlike$healing$`issures$
Photos © H.A. Hänni, SSEF
© Swiss Gemmological Institute SSEF
CrQenriched$growth$layers$Photo © H.A. Hänni, SSEF
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The Kashmir - Madagascar challenge !
The Kashmir - Madagascar challenge !
Photos © H.A. Hänni, SSEF
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Madagascar sapphire
Inclusion photos © H.A. Hänni, SSEF
Madagascar sapphire
Inclusion photos © H.A. Hänni, SSEF
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Madagascar sapphire
Inclusion photos © H.A. Hänni, SSEF
The blurred picture: Sapphire
© SSEF Swiss Gemmological Institute
Regular$growth$in$basaltic$sapphires$$Overlapping$irregular$growth$(heterogeneous$growth)$
Photos: © H.A. Hänni, SSEF
The Kashmir – Basaltic (e.g. Pailin) mix-up!
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Ceylon sapphire
© SSEF Swiss Gemmological Institute Photos © H.A. Hänni, SSEF
UV-Vis Spectrometry
© SSEF Swiss Gemmological Institute"
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© Swiss Gemmological Institute SSEF
Raman microspectrometry
Laser Ablation Inductively Coupled Plasma
Mass Spectrometry LA-ICP-MS
© SSEF Swiss Gemmological Institute
With Prof. Thomas Pettke !at the Geochemical Lab, !University of Berne, Switzerland!
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© Swiss Gemmological Institute SSEF
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
Lambda$Physics,$Coherent:$Pulsed$nanosecond$$ArF$excimer$laser$(193$nm)$
Microlas$system:$Beam$modulation$optics$to$homogenize$laser$beam$energy$pro`ile$
Perkin$Elmer:$DRCQe$quadrupole$mass$spectrometer$
Pettke, 2006!
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© Swiss Gemmological Institute SSEF
Laser ablation
© T. Pettke,, University Berne
Local$heating$and$vaporization$
© Swiss Gemmological Institute SSEF
Important: Standardised Operation Procedures
Q Laser$drill$holes$generally$60Q120$microns$(=0.06Q0.12$mm)$large$and$only$a$few$microns$deep.$Q External$standardisation:$NIST$SRM$610$or$SRM$612$glass$standards$Q Internal$standardisation$for$corundum$usually$99.5$wt%$Al2O3$Q Carrier$gas$helium$admixed$with$hydrogen$for$better$ablation$yield$and$transport$Q To$correct$for$any$possible$instrumental$drift,$each$analytical$series$starts$with$two$analyses$on$
the$multiQelement$standard$(SRM$610$or$612),$followed$by$maximum$16$analyses$on$the$samples,$and$`inished$with$two$analyses$on$the$standard$again.$
$$
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© Swiss Gemmological Institute SSEF
Features of LA ICP MS
+$nearly$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$$$$$(from$subQppm$to$main$element$concentrations)$+$quantitative$data$
Q $slightly$destructive$analysis$(laser$drill$holes$diameter$ca$100$µm)$Q $how$representative$are$point$analyses$for$the$whole$stone?$Q $raw$data$(qualitative)$has$to$be$processed$to$get$quantitative$data$Q$contamination$effects$Q $spike$`iltering$Q $highly$sophisticated$instrument$$
Chemical$analysis$of$specimens$
Photo:$Aeschlimann,$2003$
© Swiss Gemmological Institute SSEF
Research study with LAICPMS on sapphires
Photo$©$P.$Halicki,$SSEF$
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© Swiss Gemmological Institute SSEF
Data processing
LA-ICP-MS Pearls
10
100
1000
10000
100000
1000000
10000000
100000000
30 40 50 60 70 80 90 100 110 120
time (sec.)
co
un
ts
Mn
Ca
I
Ba
Mg
homogeneous$signal$
Setting$of$integrals$for$data$processing$is$easy$
Integration time
Raw data
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Surface$contamination$!$
Spikes$!$ Spikes$!$Spikes$!$
Surface$contamination$!$
Data processing
© Swiss Gemmological Institute SSEF
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Madagascar!
Kashmir!Sri Lanka!
Burma!
Fe-(ppm
)-
Ti-(ppm)-
Results:
Madagascar!
Kashmir!
Sri Lanka!
Fe-(ppm
)-
Ga-(ppm)-
Results:
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Madagascar$
Kashmir$
Burma$
Madagascar!
Kashmir!
Burma!
Ti-(ppm
)-
Mg-(ppm)-
Results:
20.12.2011 75
© Swiss Gemmological Institute SSEF
24.04.2012
Zentraler Weiterbildungskurs SGG
30
Comparison
Peucat et al (2007) Kashmir this study
Trace$element$concentrations$generally$indicate$origin$„trends“,$but$are$often$not$resulting$in$conclusive$results.$
Possibilities & Limitations:
24.04.2012
Zentraler Weiterbildungskurs SGG
30
Comparison
Peucat et al (2007) Kashmir this study
Peucat$et$al.$2007$20.12.2011 80
Thailand (Bo Phloi) + Cambodia
Peucat et al (2007)
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© Swiss Gemmological Institute SSEF
Q LAQICPQMS$is$a$sophisticated$analytical$method$$$$$$$$$to$characterise$the$chemical$composition$of$gemstones.$$Q The$machine$produces$always$results,$but$are$they$real?$$Q Many$instrumental$parameters$have$to$be$controlled$to$produce$reliable$
results.$$
Q 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$evidences.$
Conclusions:
© 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, !
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Thank you for your attention
© Swiss Gemmological Institute SSEF