The Pearl Symposium, Bahrain I November 2019
Presentation by Dr. Michael S. Krzemnicki, SSEF with Dr. Laurent E. Cartier, Dr. Bertalan Lendvay, Dr. Nadja Mort, Dr. lrka Hajdas, Dr. Vincent Revol, Carina Hanser.
"[Pearls] occupythefirstrank...andthevery highestpositionamongvaluables."
Pliny the Elder, Historia Natura/is
Mainduty ofgemmologicallaboratories inpearltesting:
• Separation of naturalpearlsfrom culturedpearls
Although in somecasesvery straightforward andeasy, the separation of naturalpearls from cultured pearls sometimesmayalso beverydifficult andchallenging.
Theconclusion ofpearltesting (naturalvs. cultured pearl) is always based onan educatedinterpretation of observed and analysed datapertaining to that pearl.
As such, any pearltesting conclusionisalways an expert opinion.
The Peregrina pearl, tested at SSEF.
Pearltesting is always basedon a combinationof varioustesting methods, such as:
External observation (e.g. microscopy), visualisation of internal structures (e.g. X-ray radiography}, chemical analyses (e.g. ED-XRF), structural analyses (e.g. Raman spectroscopy), to name a few.
Novel methodsareevaluatedon a continuous basistoget newinsights into pearl formation and their internal structures, andfinally with theaim to support pearltesting as aclient serviceto thetrade and consumers.
cedbycosmic on,andthustran
14� aggregatestoCO2
�cincQr.poratlon (asCO2) yphotosynthesis
14CIncorporation (asCO2) Intowaterplants
CarbonIsotopes(Including 14C)
livingorganisms(Inequilibriumwl
After th, 14Cdecaysto 14N withhalf-lifeof5700 ears
MICAOAS Mini Carbon Dating System (Accelerator Mass Spectrometer).
Image ETH Zurich & ionplusAG
Figure: M.S. Krzemnicki, SSEF Using background illustration From www.fisheriesireland.ie
A minute amount (less than 0.004 g) of calcium carbonate is takenfrom insidethedrill-hole. ,,quasi" non-destructive testingevenfor objects of archaeological and cultural heritage.
0.02 et powder of calcium carbonate for agedating.
et 21.45 et
1000 year old pearls discovered in 2003 in the Java Sea (Indonesia).
RadiocarbonAgeDatingof 1,000-Year-Olld Pear11sfromthe CllrebonShipwreck(Java,lndone&na)
MkhaelS.Krzemnkld,LaurentE.CartierandlrkaHajdas
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Documented sincemid-19th century: Originallybelonging toAna Marfa de Sevilla (1828-1861). Probably fished during Hernan Cortez's conquest of the Aztec Empirein the16th century . The radiocarbon analyses (carried out by ETHZurich) datethis pearl to the 16th - 17th century, thus perfectlymatching the documented historic provenance of this pearl.
Cultured pearls formed around the "bomb" peak in 1966 (southern hemisphere). Early production from Kuri Bay, Australia's first pearl farm (first production 1956).
In the Paspaleypearl office in Darwin with Peter Bracher
75318_3 R_Date(-350.45)
95.4%probability 1956-1958calAD 2008calAD•.
75318_11 R_Date(-4000,43) 95.4%probability 1963-1966calAD
Supporting evidence due to radiocarbon age dating
Thissaltwater pearl shows internalstructures whicharealso known in beadlesscultured pearls (Krzemnicki etal. 2010, Sturman2009).
The radiocarbon analyses (carried outby ETH Zurich)date this pearl to the 17th - 18th century, distinctly pre-dating any pearl farming. Theradiocarbon age thus supports the conclusion of natural pearl.
Micro X-ray tomographical section ofpearl centre.
Since February 2017, the SSEF in collaborationwith the Federal Institute of Technology (ETH Zurich) offers radiocarbon age dating of pearls as a service to our clients.
see: www.ssef.ch/press-releases/
The Swiss Cemmological Institute SSEF has become the first gem laboratory worldwide to introduce, as an additional service to clients, age dating of pearls using carbon-14 (l4C). This scientific method can provide the pearl industry with new valuable information about the age of loose pearls and pearls in jewellery.
• Deoxyribonucleic acid (DNA): Contains all the information an organism needs to develop, live and reproduce. It is formed by the four nucleobases (or 'bases') adenine (A), cytosine (C), guanine (G) and thymidine (T). The order of the bases (e.g.ATCGGTT...) codifies the specific instructions for any living organism.
• Genome: An organism's full set of DNA, including all of its genes.
The nacreous part of a pearl consists of approximately 92% CaCO3, 4% organic matter (OM), 4% water and minute amounts of residual substances (Taylor & Strack, 2008).
The OM (consisting mostly of conchioline and porphyrines), which is also secreted by the pearl sac, serves as a framework for the CaCO3 matrix during the biomineralization process. OM can also be found in concentrated pockets.
Quasi non-destructive:
Forrecentcoral DNAfingerprinting work we were able toextract DNAsuccessfully with as low as2.0 mg sample material.
Methodologypublished in 2013 in PlosOne
DNA Fingerprinting of Pearls to Determine Their Origins
JoanaB.Meyer'...LaurentE.C.rtie,.,...,EdeA.Pinto-Figueroa•,MldlaelS.Krumnidd2, tt.nryA.Hiinnl',BruceA.McDonald' 1�ol&o....,,...,,....S,...,Sdwoc«,.So.m:r.t..ilimlubJdTdwlalogy,a...iicf\
In.tu..SS&',...._s-iturtwod. !�off:rlwirarl__,_.Sciwo-,.t.Hw.sitfdlnt(......�.4o.p..tmn:d&olagy.-.:lhoMian,l.Hwwikydt...-1,..,..._,,_..._�4 s�.....�
Abstract
Wereportthefirstsuc�ssftJextractionoloysterONAfromapea,tanduseit toidenttytheSOUf<roystersprdesforthe dweemajorpearl,produdngoysterspedesPinctodJmo,gotitfftd,P.mdl'inoandP.rodiiJta.Bothmitochondrialandnudear genefragmentscWdbePCR-amplfiedand sequenced.Apalymer-asediain ructiai-restriction fragmert length polymoq,l,ism(PCR-RR.P)assayin11l•in,.maltranscribedspoc,.0TS)l'9iof1wasdowl-dandUS<dtoid<nti(y18poa,ts olunknownoriginAmicro•drHngtechniquewasdevelopedtoobtaiii:smalamounts d ONA'Mllemairtainingthe ccm,ne,tiMvaluedthepeads..ThisDNAfingerprintingmethodcouldbeus«ttodoa.Jmeitthesourceofhistoricpeads andwilp-CMdtmotttran$plfencyfa-tradersandconsumers-.-Athinthepea,1industry.
b.don!..,_...c.tiwlf.ArcoRgu--.tA..�MS.HfmlHA.,ttlf(2013)C,,,AA,ppk,!ingof'-tsto0.....,,._1h.,OignFt.oSarl!t(1(1l, !,(,(16cbl:101371p.millp>N007'JtlCl6r:lonludoricOrllndo,NmillllMstcryMuuund0.-.,....._U,.._itydCqMrohlg-.o-'b «.efv.rMadi�2013;�Augu,tl�2013;PublshedClttd>w9,.201:\ opy,igh4:10201:\..,_.ttIfffish:.-...-.�Micitd�..-.dtrtt...-,nsdtt.c...ittw.C-.sMrbu6of'l...,_.--..t.khpwrils ,_�\H,d�vtdfllPID(ll.doflkl¥¥n.diurn,.prorrofdl,dto•Gl9'illllachot'.-.dSOUct-adbd undl"91Th•stuc11-�bytt.Swiss�--..sfb.b(95&)1h•iind-hdrodltilstu:lydilairJnda�vtd....,.__.....to l::Adl,ar.......,.ofto•ffWWIU'lp: °""'ld"'IJl�th•ait,ors:'-dks..d"•no�il�tsmsl t,,.;...�_.can'8Mlg....,.,_.tct. UQ
• Thenegativelycharged DNAmoleculeis known to havea highaffinity for the Ca2+ ion of CaCO3, which mightenhanceits conservation in pearls and corals.
• EDTA (0.5M pH=8, overnight56°C) used to liberateDNAfrom CaCO3 matrix.
Source: Sommerdijk et al. (2007)
• Kit needed to concentrate DNAfrom recovered sample powder.
• Having positive and negative controls is critical.
• Depending on the species to be identified, different markers in the genome are targeted (e.g. ITS2, 16S, Cox1, Cox2).
• DNAamplification involves using short DNA sequences (primers) to select the portion of a genome for amplification. In PCR, sample is repeatedly tempered to help a DNAreplication enzyme synthesize the target DNA sequence.
• PCR can produce thousands to millions of copies of the target sequence, to be then analysed by visual inspection (e.g. gel electrophoresis) or by sequencing.
Source: Garibyan andAvashia, 2013
500 "1>. maxima P. radiata P. margaritifera
200 ----
DNA species identification of pearls will be soon available as a service to our clients. -
0.001 H
97 .-----P.mscu/a/4
P.lmbricata{Aooda,USA)
radJSta(PeruslanGu
Pfllcala
5 (Namakoilce Kagoshima Japan)
P.fucsla(Myanmai)
39 42
P.lucata (Camtxxll�
21 P.fucara (Per111, Australia)
31 P./ucata(Chlna)
4 P.fucata (Amaml, Kagosnima,Japan)
65 P.maJtensii (Anamlzu,l&hlkawa,Japan)
• DNA species identification of coralswillbesoon availableas a servicetoour clients.
• SSEFoffers this servicein collaboration with the Institute of Forensic Medicineof the University Zurich, Switzerland
Hasso Nehanzu, 1772
Sample CB009 from CoralliumJaponicum
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• Ivory is any mammalian toothortusk ofcommercialinterest.
• African (Loxodontaafricana) andAsianelephants (Elephas maximus), alongwith their fossil relatives (e.g. Mammuthus sp.) belong to the mamallianorder Proboscidea.
Laurent E Cartier, Michael s. Krzemnicki, Bertalan Lendvay and Joana B. Meyer
Since September 2019, theSSEF in collaborationwith the Institute of Forensic Medicine
(University Zurich) offers DNAspeciesidentification of ivoryas a service to our clients.
see: www.ssef.ch/press-releases/
IDENTIFICATION OF IVORY AS CLIENT
SSEFlaunchesa servlces that providesa scientific methodto identffythe speciesofivory being usedinjewelleryand ornamentalobjects, in order to determine whetherit is CITES-listed elephant ivory ornon-listed mammoth ivory.
Since decades, X-ray radiography (attenuation) is the most important methodto visualise internal structures in pearls.
X-RAY COMPUTED MICROTOMOGRAPHY: DISTINGUISHING NATURAL PEARLS FROM BEADED AND NON-BEADED CULTURED
X-ray microtomography allows 3D visualisation of internalstructures in pearls.
platelets (nacre)
isshoY.ntobeapowerfultoolforpearl
dwTnnt:iiin0-i.M.,•tidPtnia stmu inMeicico..ucuJ. tivuioa11edo.n.i4Uet1hii.\'IC.i�dfHiani,1007),thedi, ti.nction 1'��n,uulllltndcultured.-,rl,�bco:,,ou:. mendi:fficu.Jt(,t:,c,e-.g.,Saiinrtt�toJ.,UCO;Alwtllltsu�t tl,200I;Hanoi,2006;StumuntndAl-Att.llWi,2006; Stwnuoa,2009J,o.nd�pmlictitwill��mottoulbt;iQSinlMfuture, Ford««k,i.now,�,�..:Jit:dpri.nmi]y011. X-ndios�fortbt,eptntiooolN0..-.1homculturtd pe,,uhfY;'d,�tiei-,199�Sn.irnwn,2C09;ondidt:tto..-du,tt. i.nJ.CM!y..eomttrh,uX-nayo:,,i;npuk'<lntic11011:1n�Ql))by
Byusingtwomovinggratings,itis possibletogetsimultaneouslythree X-rayimagesofapearl: -absorption(classicradiography) -refraction(phasecontrast) -andscattering(darkfield)
Absorption
Beaded cultured pearl (SW) in radiography, phase contrast, and darkfield imaging
Structures which are difficultto see in classic radiography can be observed in phasecontrast and darkfield imaging with more detail
in radiography, phase contrast, and darkfield imaging.
FeatureArtlcle
Simu!1tarnecmsX-Radliography, Phase-Contrast ar1dl Darkfieidl imaging ro Se1Para1te Naturalfrom Cu!1t11J1red Pearls
Michael S. Krzemnickl,Garina S. HanserandVincentRevol
TheseparationotnaturalfromculturedpearlsIsmainlybasedontheInterpretationoftheirInternalstructures,whichtraditionallyhaw,beenvisualizedby X•radlographyandmorerecentlybyX-rayoomputedmicrotomograim,(microCT).Inthisstudy,theauthorspresentanewanalyticalapproachusingagrating Interferometer,wtlichsimultaneouslygeneratesanX-radlograpn,aphase-coo•
Contentsliatsavailable atScienceOirect Case Studies inNondestructiveTestingand Evaluation
illl:VU:.k wwwelseviercomllocate/csndt
Characterizationof pearls byX-ray phase contrast imaging with agracing interferometer
Vincent Revol'•*, Carina Hanserb , Michael Krzemoicki0 •CS£11S4u.cm,.Q,•4iihwst I 6055M,-.cl0otf5'rictl'l"'-I "sstFSdwlodtcri:cdlesC-i!lotJts,dt,t.s.k.._Aedt-,ollll!lJS'951 lo."'S.,hffl•4
ARTICLE INFO AISTtACT
trastImageandasmall-scale scatteringordarkfieldimage.Thelattertwoad- AnldtMrt-, 10thisstudy.x-ray Jbase oootrast1.mag1ngwith a
�nalImagesprovidedbythlstechniqueofferdetailedandoomplementa,y Anil�01111M•J-2>t&
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It iseven possible to do X-raytomography in phase contrast or darkfield modes.
30 rendering of natural pearl in darkfield (scattering) mode. red arrow: organic rich spherical core, green arrows: onion-like growth structures in nacre.
The neutronbeamforimaging is produced at SINQ spallation source (PSI Switzerland).
PSIproton accelerator produces beam of fast protons(~ 80 % of the speed of light).
Proton beam strikes a block of lead (target). If a fast proton collides with alead nucleus, the nucleus will beheated up and ejects 1o to 20 neutrons.
IINeutron •Proton Lead
- These neutrons are slowed down by collisionswith the nuclei of heavy water(deuterium) to be used as neutron beam for imaging analyses.
fhe PSI Cockroft-Walton accelerator - the first stage of the proton acceleratorfacility
Photos and Scheme: Paul Scherrer Institute PSI
While X-rays are attenuated more effectively by heavier materials like metals, neutrons make it possible to image some light materials such as hydrogenous substances with high contrast:
:Neutrons I
Interaction behaviour ofdifferent atoms withX-rays and neutrons. The larger the diameter, the stronger the interaction (absorption).
Radiograph ofa camera by neutrons (top) showing details ofthe plastic parts and by X-rays (bottom) revealing the metal parts ofthe camera.
Neutron images are best analysed by direct comparison with X-ray images.
Beaded cultured pearl in X-ray radiography and neutron radiography, revealing the inverse absorption behaviour of these two emission sources with organic matter (hydrogen-enriched) in pearls
red arrows: organic layer (conchioline) wrapping the inserted bead in this cultured pearl.
Similar toX-rays, itis also possible touse neutrons for microtomography.
Natural pearl (Pinctada maxima) from NWAustralia (Paspaley)
Carina S Hanser, Michael S. Krzemnckl, ChristanGrOnzwelg, Ralph P. Hartt, Benedlkt Betz and David Mannes
N�emugiogoftbeinternalstructure8ofpearlsbaseo£3rbeenmainlybasedon X-ray�methods.Asorganicmatterisalmo8ttransparenttoX-raya,theidentification ol.somestructu.reecanbedifficu.lt.Tb.isstudy&bowsthatneutrooiougiogcanbeahelpful ocmptementarymethodtovisualizestructweeinsidepeadsbeyondstandardX-t'ayra::tiograpby andtcmograpby,asneutromarehighlyattenuatedbyh}'drosen-bea.ting(organic)matterwithin pealh,Theu&eofneutrooradiographyandtomographyisshownfar&electednaturaland culturedpeads(beadedandnon-beaded).Inaddition,wepresentneu.tron_pha.&eOOQlJ'astand darldieldimag\'sof.abeadedcu.ltundpearl,inanalogytoX-rayphasecontrastanddarld:ield imagine:de8cribedinapreviousstudy,Whilerwutronimagingofpearbispartirularlyuseful forUlde:tsta.tdingmaterialinhomogeoeitie&andvoid&tructw-es,thismethodologyiscuuenlly olllyavailableat�scale£adlitieslbatareequippedtodealwithnuclearreactions.
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INTRODUCTION
Faraboutacenu.ry,theldentlfl.cattonof pearls(I.e.d1fferenU:atlngbetWffllthe.it nanua1orC-ultu.redfurmatton;Ftgu.re1) ha.&beenacrucialtaskforgemmoloSIJtS.giventbeenoanowdtfft'f'eDCesIntbetrrutty andpdoe,Peadtdeotl.fkattonumostlybasedon thetntetpretattonoftDlernalstructures,tradttton• allyvtJuallt.edbytmaetn8methodsauchasX�r.ay -(And<non,1!112.;S<mattEtal,2000; Strack,2006;Stwmao,2009),ad,more,.,,,.,.ly, X-raycomputedmJaotomography{Wemmelster« al,2009;Kmmpew«a1.,211ro;Kfflemnlclcl"al, 2010;Oneretal,201')aodX�raypha&ecootrut andclarktleld-(R,Yol«al,21116;KaRm• Olckle<al,21111).
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tbeSSEFSwtatG�Jmmutea.ndthePaul ScbemrInstitute,mwl:ithatotalotn,amp1,e,(13 naturaland19culturedpearlt)weretnvffllgated wtththeatmotcompar:togvamuslm.aglQgmdbodt forpearlteftlng(Ha.n&er;2015).Itbafollow-upto thea.rttdeaboutX�rayphaseoontraJtandda.ddkld tmaglQgthatwa.slMentlypubli&bedlnTh�JOIITIIJl. (1(mmnJcldEtal,21117).
StmllartoX•raya,neutronscanbeappbe,ifor tll\ag1qJpu.tpOffl,becauteoftbetreelecUveatteoua• tlOnVlaabsotpl1onmiKattedQgbyC«tal.nmatedals. ButuolikeX•rays,neuttonslllleractwtththeatomic nudetooly.Thu1,.eventomelf&btereleneou,uch asbydrosenI0:'0IQg1y"attenuateruuttooa,whereat X•nys(wbldltoteractwtlbtileelecaoo9otatoms) a.reverywea.klyatteouatedbyUgbtelemeatsanda.re """"""'elal1ecc,dby--·(cbn!c:tly ttlatedtotheelement',atomicn�.Geoerally spealdt)g.neu1ronradiographyImagesareIOV'eneto
• Today, new scientific methods are available for pearl testing, these include:
- Radiocarbon age dating using 2-3 mg of nacre ("quasi non-destructive") as client service.
- DNA species identification using 2-3 mg of material ("quasi non-destructive") as client service.
- Novel imaging methods, such as X-ray phase contrast and darkfield radiography and tomography and neutron radiography and tomography.
• However, conclusions of pearl testing still are (and will be in future) expert opinions based on the educated interpretation of observations and data.
• Scientific research on pearls, their formation, and their internal structure are fascinating topics which require a multi-disciplinary approach involving mineralogy (biomineralisation), biology, forensics, and the latest imaging technology.
www.ssef.ch/ssef-facette