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© Swiss Gemmological Institute SSEF
The beauty of colour
Dr.$Michael$S.$Krzemnicki,$Swiss$Gemmological$Ins9tute$SSEF$$
Photos$©$M.S.$Krzemnicki,$SSEF,$except$where$indicated$otherwise$
ScoCsh$Gemmological$Associa9on$E$Conference,$Saturday$3$May$2014$
The quest for "Kashmir" sapphires and "Burma" rubies
Origin determination of gemstones: Possibilities, Challenges and limitations !
The$Star%of%Kashmir%Sapphire$from$Kashmir$of$approx.$20$ct,$$Geneva$May$2013,$3.5$mio$US$$SSEF$Test$Report$No.$66221$
Burmese ruby
A$superb$ruby$of$6.04$ct$set$in$a$ring$with$diamonds$by$Etcetera.$$$Sold$for$a$world$auc9on$record$price$of$US$$551‘000$per$carat$(Chris9e‘s$Hong$Kong,$May$2012).$$SSEF$report$59356$&$Appendix.$$
Photo$©$Chris9e‘s$
A$number$of$sources$of$coloured$stones$are$known$since$historic$9mes$and$their$gems$have$been$treasured$over$centuries$for$their$beauty$and$rarity.$
Bagan,$Burma$©$P.$Boegli,$Flickr.com$ © Swiss Gemmological Institute SSEF
The$relevance$of$the$origin$of$a$gemstone$E emo9on$E connec9ng$to$history$E a$label$E for$investment$
© Swiss Gemmological Institute SSEF
Relevance$of$origin$$Prices$$Auc9on$$$Etcetera$ruby$!$$Emo9onen$$Label$$Sicherheit,$Wertanlage,$investment,$$$Exper9se$as$with$art$work$(Rothko)$$$$
Rothko:$un9tled$
Jose$Boomsma:$Tribute$to$Rothko$EBlue$
Origin determination is always an expert opinion !
© Swiss Gemmological Institute SSEF
The$origin$determina9on$of$gemmological$laboratories$is$always$based$on$scien9fic$analyses$(e.g.$trace$element$composi9on,$absorp9on$spectra,$Raman$microspectrometry$etc.)$and$me9culous$
microscopic$observa9ons.$$
Thus$it$is$possible$that$two$different$labs$may$issue$a$different$origin$for$a$given$gemstone.$
© Swiss Gemmological Institute SSEF
Origin determination:
Combining(classical(approaches(with(advanced(scienti5ic(analytical(methods(
The$origin$of$a$gemstone$on$a$report$is$always$an$opinion$of$experts,$indica9ng$its$most$probable$geographic$origin.$$It$describes$stones$which$originate$from$a$mining$opera9on$in$that$geographic$area.$$It$is$related$to$the$geological$seCng$$characteris9c$for$the$origin$(mining$area).$$The$origin$is$expressed$based$on$wellEestablished$criteria$(e.g.$inclusions,$chemical$composi9on...).$$$Challenges:$$E $New$mining$areas$are$discovered.$
E$The$analy9cal$methods$get$more$and$more$sophis9cated.$
© SSEF Swiss Gemmological Institute
Near$Bawpadan$in$Mogok$
Origin$determina9on$at$SSEF$is$relying$on:$$E $$scien9fically$and$gemmologically$highly$educated$staff$$
E $sophis9cated$analy9cal$instrumenta9on$
E $reference$samples$from$different$mines$
E $con9nuous$research$
E $long$established$experience$
© SSEF Swiss Gemmological Institute Photo © H.A. Hänni, SSEF 2004
© Swiss Gemmological Institute SSEF
$1)$Observa9ons$and$collec9on$of$analy9cal$data$$2)$Interpreta9on$of$observa9ons$and$data$$3)$Weigh9ng$of$evidences$and$consistency$check$$4)$Conclusion(s)$$$$Important:$Independent$assessment$of$a$gemstone$by$second$(third$etc...)$expert$(gemmologist)$and$mutual$discussion$!!$
Four steps of origin determination:
Deposits connected to Pan-African tectonometamorphic events
Distribu9on$of$corundum$deposits$connected$to$PanEAfrican$tectonoEmetamorphic$events$(750E450$ma)$by$the$collision$of$eastern$and$western$Gondwana.$$In$midEJurassic$(about$160$ma),$India$started$to$drig$towards$north.$
Distribu9on$of$marbleEhosted$ruby$deposits$along$the$Himalayan$orogeny$(45E5$ma)$due$to$the$collision$between$the$Indian$plate$and$Eurasia.$$
Dahaw$mine$:$Mogok$East$
marble-hosted deposits
after Jobbins & Berrangé, 1981
Corundum from alkali basalts
Ter9ary$and$quaternary$basalts$and$related$
corundum$deposits$in$SouthEEast$Asia.$
Jobbins & Berrangé, 1981!
Pailin!
Analytical instruments used for origin determination at SSEF
$E XEray$fluorescence$(EDXRF)$E Raman$Microspectrometry$E FTIR$Infrared$Spectrometry$E UVEVisENIR$Spectrophotometer$E Photoluminescence$
Eventually:$E LAEICPEMS$(laser$abla9on$induc9vey$coupled$plasma$mass$spectrometry)$E LIBS$(laser$induced$breakdown$spectroscopy)$
© Swiss Gemmological Institute SSEF
© Swiss Gemmological Institute SSEF
Raman microspectrometry
UV-Vis Spectrometry
© SSEF Swiss Gemmological Institute"from H.A. Hänni, Journal of Gemmology 1994!
Chemical data versus spectroscopic data
© SSEF Swiss Gemmological Institute!
Basaltic!
Kashmir!
Burma!
Ceylon!
Laser Ablation Inductively Coupled Plasma Mass Spectrometry LA-ICP-MS
© SSEF Swiss Gemmological Institute
With$Dr.$Thomas$Pehke$$at$the$Geochemical$Lab,$$University$of$Berne,$Switzerland$
© Swiss Gemmological Institute SSEF
Laser ablation
© T. Pettke,, University Berne
Local$hea9ng$and$vaporiza9on$
© Swiss Gemmological Institute SSEF
Data processing
LA-ICP-MS Pearls
10
100
1000
10000
100000
1000000
10000000
100000000
30 40 50 60 70 80 90 100 110 120
time (sec.)
co
un
ts
Mn
Ca
I
Ba
Mg
homogeneous(signal(
Setting(of(integrals(for(data(processing(is(easy(
Integration time
Raw data
From:$P.$Halicki,$SSEF$(Masterthesis)$
Surface$contamina9on$!$
Spikes$!$ Spikes$!$Spikes$!$
Surface$contamina9on$!$
Data processing
From:$P.$Halicki,$SSEF$(Masterthesis)$
© Swiss Gemmological Institute SSEF From:$P.$Halicki,$SSEF$(Masterthesis)$
Madagascar!
Kashmir!Sri Lanka!
Burma!
Fe#(ppm
)#
Ti#(ppm)#
Sapphire Results:
From:$P.$Halicki,$SSEF$(Masterthesis)$
Madagascar!
Kashmir!
Sri Lanka!
Fe#(ppm
)#
Ga#(ppm)#From:$P.$Halicki,$SSEF$(Masterthesis)$
Sapphire Results:
Madagascar(
Kashmir(
Burma(
Madagascar!
Kashmir!
Burma!
Ti#(ppm
)#
Mg#(ppm)#From:$P.$Halicki,$SSEF$(Masterthesis)$
Sapphire Results:
20.12.2011 75
© Swiss Gemmological Institute SSEF
24.04.2012
Zentraler Weiterbildungskurs SGG
30
Comparison
Peucat et al (2007) Kashmir this study
Trace(element(concentrations(generally(indicate(origin(„trends“,(but(are(often(not(resulting(in(conclusive(results.(
Possibilities & Limitations:
24.04.2012
Zentraler Weiterbildungskurs SGG
30
Comparison
Peucat et al (2007) Kashmir this study
Peucat(et(al.(2007(20.12.2011 80
Thailand (Bo Phloi) + Cambodia
Peucat et al (2007)
From:$P.$Halicki,$SSEF$(Masterthesis)$
Kashmir sapphire
The(Maharaja(of(Jammu(and(Kashmir,((circa(1900(www.kashmirphotos.org/history.html(
The velvety blue of Kashmir sapphires
Sapphires$from$Kashmir$contain$subEmicroscopic$inclusions$which$scaher$the$transmihed$light.$$$As$a$result,$these$stones$ogen$show$a$$highly$appreciated$velvety$blue$colour.$
Photo © H.A. Hänni, SSEF
© Swiss Gemmological Institute SSEF
Characteristic inclusions in Kashmir sapphires
healed$fissure$with$interrupted$fluid$tubes$
Subtle$„dust“$tracks$
Photos: © H.A. Hänni, SSEF
Zoning$pahern$no$ru9le$needles$in$Kashmir$sapphires$!$
Pargasite$needles$(prisma9c)$
ShortEprisma9c$greenish$dravite$(tourmaline)$ Prisma9c$but$corroded$zircons$
Characteristic inclusions in Kashmir sapphires
Corroded$plagioclase$ Photo © H.A. Hänni, SSEF
Photo © H.A. Hänni, SSEF
The Kashmir - Madagascar challenge !
© Swiss Gemmological Institute SSEF
Origin$determina9on$=$combina9on$of$data$$$
Kashmir- Madagascar-
Blocky$zoning$with$red$VISEfluorescence$ Very$dense$zoning$
„Parquet“Estructure$ Dark-grey-colour-layer-(zone)-
Photo © H.A. Hänni, SSEF
© Swiss Gemmological Institute SSEF
Origin$determina9on$=$combina9on$of$data$$$
Kashmir- Madagascar-
subtle$„dust“$flakes$and$patches$
dense$and$wellEshaped$(rhombic)$„dust“$patches$
Photo © H.A. Hänni, SSEF
© Swiss Gemmological Institute SSEF
Origin$determina9on$=$combina9on$of$data$$$
Kashmir- Madagascar-
Fine$and$partly$curved$„dust“$lines$and$tracks$
Dis9nct$and$straight$„dust“$lines$
Photo © H.A. Hänni, SSEF
© SSEF Swiss Gemmological Institute
Characteris9c$$blocky$zoning$
Kashmir – Sri Lanka – Madagascar - Basaltic
ogen$narrow$zoning$
ogen$narrow$zoning$with$dark$zones$
Very$regular$$narrow$zoning$
Usually$$quite$included$
Ogen$$rather$pure$
Ogen$$rather$pure$
Usually$$included$
Characteris9c$$Inclusions:$E$pargasite$...$
Characteris9c$Inclusions:$
E$apa9te,$diaspore...$
Ogen$only$$few$inclusions$
Characteris9c$$Inclusions:$
E$UEpyrochlore$
Metamorphic$$UVEVis$spectrum$
Metamorphic$$UVEVis$spectrum$
Metamorphic$$UVEVis$spectrum$
Basal9c$UVEVis$spectrum$
Low$Fe$Low$Fe3+$
Low$Fe$Slightly$higher$Fe3+$
Higher$Fe$Slightly$higher$Fe3+$
High$Fe$High$Fe3+$
New source: Fancy sapphires from Batakundi, Kashmir area (Pakistan)
Sleeping$beauty$?$
New source: Fancy sapphires from Batakundi, Kashmir area (Pakistan)
Usually$included$(graphite),$milky$and$with$dis9nct$colour$zoning$(Cr).$
© Swiss Gemmological Institute SSEF
Ruby
Burmese ruby
© Swiss Gemmological Institute SSEF
The$ruby$ring$of$Marie$José,$Queen$of$Italy$
Courtesy of Albion Art collection!
Mogok
Gemmarket$in$Mogok$(January$2014)$
Dahaw$mine$:$East$of$Mogok$
Introduction
Jade,(since(thousand(of(years(a(mythical(stone(appreciated(in(Far(East(and(in(the(high(cultures(of(native(Americans,(is(currently(again(rising(high(and(is(sought(after(at(auctions(in(Hong(Kong(and(elsewhere.((
Ruby-tes<ng-at-SSEF-
The$quest$for$the$perfect$ruby$from$Mogok...$
approx.$14$ct$
Inclusions in Ruby from Mogok
!!!
Ru9le$silk$ Calcite$crystals$
Twin$lamella$ Corroded$calcite$crystals$
Photos © H.A. Hänni, SSEF
Colour$swirls$
© SSEF Swiss Gemmological Institute"
Generally$included$
105$ct$
© SSEF Swiss Gemmological Institute"
Titanite$and$plagioclase$inclusion$in$ruby$from$Mogok$ www.op9cs.rochester.edu$
www.vcbio.science.ru.nl$
www4.nau.edu/microanalysis$
Scanning$Electron$microprobe$
Burmese$Ruby:$approx.$48$cts$
Approx. 48 cts!
„Cut$tongues“$and$geometric$(trigonal)$platelets$
Mong Hsu, Burma important source of rubies since the 90ies!
Many rubies from Mong Hsu have a dark blue core
Mong Hsu, unheated
Dark$blue$to$black$core$zone$(TiEenriched)$
Mong Hsu, unheated
Cross$clouds$ Dust$tracks$„comets“$
Mong Hsu, unheated
Zoning$$$
&$healed$fissures$
Carbonates$
Mong Hsu heated LW$UV$reac9on$
SW$UV$reac9on$
Photos © H.A. Hänni, SSEF
New Ruby Deposit: Montepuez in Mozambique
Photo © H.A. Hänni, SSEF
Mozambique (Montepuez) Rubies$from$Amphibolite$
Photos © H.A. Hänni, SSEF
Inclusions:$$Rounded$crystal$inclusions,$$ru9le$needles,$twinning$planes,$$green$amphibole.$$E$Inclusions$±$similar$to$Mogok,$Burma$E$Trace$elements$±$similar$to$Winza$
Montepuez Ruby
© Swiss Gemmological Institute SSEF
Photos © H.A. Hänni, SSEF
© SSEF Swiss Gemmological Institute
Ruby from Winza (Central Tanzania)
Photo © H.A. Hänni, SSEF
Rubies from Winza
Characteris9c$inclusions:$$
E$curved$hollowEchannel$
E$whi9sh$granular$fluid$inclusions$
E$blue$to$greyish$colour$zones$
© H.A. Hänni, SSEF
Colour zoning in corundum from Winza
© Swiss Gemmological Institute SSEF
Vive la France!
New rubies and sapphires from Madagascar (Didy):
A(ruby(of(25(ct(from(Didy((Madagascar)(showing(an(exceptional(clarity(
The Cinderella job....!
Unheated Burmese rubies mixed with very few heated ones, or even synthetic rubies or ruby imitations (dyed quarzite)!
© Swiss Gemmological Institute SSEF
The colour of ruby
ruby(
pink((sapphire(
purple(
Pigeon$blood$red$$SSEF$defini9on:$Poe9cal$and$historical$colour$term,$describing$a$saturated$and$vivid$crimson$red$colour$of$gemquality$untreated$rubies$from$Burma$(Myanmar).$$The$SSEF$does$not$apply$this$term$to$rubies$from$other$sources,$nor$to$heated$stones.$$At$SSEF$$stones$are$compared$to$colour$charts$and$reference$stones.$
Conclusions:
Origin$of$a$gemstone$should$not$be$misinterpreted$as$a$quality$grade.$$Origin$determina9on$is$always$a$expert$opinion$$It$is$based$on$a$combina9on$of$me9culous$observa9ons$and$analy9cal$data$$New$analy9cal$methods$have$made$and$will$make$important$contribu9ons,$but$due$to$overlapping$proper9es,$these$data$need$careful$interpreta9on$(no$black$box$!)$$S9ll$nowadays,$microscopy$is$a$very$important$and$useful$tool,$as$the$presence,$shape,$and$distribu9on$of$inclusions$and$zoning$features$are$very$sensi9ve$markers$of$specific$local$forma9on$processes.$$New$deposits$may$be$a$challenge$for$gemmologist,$but$are$welcomed$by$the$trade$to$answer$the$high$demand$in$gems.$$$
Thank you for your attention
For$more$informa9on,$check$www.ssef.ch$