SSEF News
Dr. Michael S. Krzemnicki Swiss Gemmological Institute SSEF
Photos © M.S. Krzemnicki, SSEF, except where indicated otherwise
SGG Zentralkurs Thun 16. April 2013
© Christie‘s Hong Kong
© Swiss Gemmological Institute SSEF Mineral(identi+ication(by(chemical(analysis((e.g.(EMP)(and(structural(analysis((XRD,(FTIR,(Raman)( FTIR(spectra(of(jadeite( ©(Shurvell(et(al.(2004( 05.03.13 19:26section2.htm http://www.ijvs.com/volume5/edition5/section2.html Figure 7. Infrared spectra of a sample of jadeite (A), a carved jadeite elephant (B) and a green/white cabochon (C). There are small differences between the spectrum of the sample scraped from the jadeite elephant (B) and the other two spectra of Figure 7 (A and C). The position of the maximum of the very strong absorption band near 1100 cm is lower in the spectrum of the jadeite elephant (1068 cm-1) than in the other two spectra (1090 and 1086 cm ). Also, the relative intensities of the absorptions near 510 cm-1 (broad shoulders) and 460 cm-1 (strong sharp peaks) are reversed in the jadeite elephant spectrum, with the first becoming a strong broad band Raman Spectra of Some Jadeite Jade Objects Figure 8 shows the Raman spectra of four jadeite jade objects. The upper two of these spectra (A and B) were obtained using the FT-Raman spectrometer. The lower two spectra (C and D) were recorded using the Raman microscope. In Table 4 the wavenumbers reported by Smith and Gendron [8] for Burma jadeite are compared with the wavenumbers observed in the Raman spectra of two 0" 2000" 3000" 4000" 6000" 7000" 8000" 100" 200" 300" 400" 500" 600" 700" 800" 900" 1000" 1100" 1200" counts' Raman'Shi.'cm/1' Jadeite"(Burma)" Jadeite"(California)" Kosmochlor" Omphacite" Diopside" Aegirine" Augite" ©(M.S.(Krzemnicki(with(data(from(RUFF(Raman(database( Jadeite rock textures © Swiss Gemmological Institute SSEF Complex(textures( unveil(a(complex( geological(formation.( © T. Cheng
Black(chromite grain with +ibrous kosmochlor((green)(and surrounded by +ine(granular(( colourless jadeite and greenish(larger(richterite((amphibole)(formed during(retrograde( CaRsupply Photo(©(L.(Franz,(University(Basel( Jadeite from Kazachstan Itmurundy
Jadeite grain with brownish omphacite ongrowth((Ca metasomatism)(in(jadeite jade(from Kazachstan Photo with crossed polarizers.(©(K.(Ernst,(University(Basel( Gemtrade Nomenclature © Swiss Gemmological Institute SSEF CIBJO:'' The'World'Jewellery'Confederation Jade is(a(general(term(describing(two(different(minerals((jadeite(and(nephrite)(in( their(massive(form,(as(polycrystalline,(quasiRmonomineralic(rocks.(The(term( jade(is(usually(used(as(a(suf+ix(after(the(mineral(name.( HOKLAS''' The'Hong'Kong'Laboratory'Accreditation'Scheme'(ISO'17025;'2006)' Fei'Cui' is(a(granular(to +ibrous polycrystalline aggregate.(It is composed of jadeite as major mineral It may consist of other minor minerals(such(as omphacite,( kosmochlor,(amphibole and feldspar New'addition'2013'to include omphaciteR(and kosmochlorRjade(into the(Fei(Cui( de+inition((GAHK)
The
Kashmir - Madagascar challenge ! © Swiss Gemmological Institute SSEF Kashmir sapphires The(Maharaja of(Jammu(and Kashmir,(circa(1900( www.kashmirphotos.org/history.html Treasured by the Maharadja
The Kashmir - Madagascar challenge !
Photos © H.A. Hänni, SSEF
Madagascar sapphire
Cobalt-bearing Zirconia as sapphire imitation Attractive(blue(colour( Kyanite as sapphire imitation Strong(pleochroism
Paraiba-tourmaline intergrown with lepidolite mica Anyolite,(fancy(trade(name(for(zoisite amphiboleRruby(intergrowth.( 728 1065 tourmaline reference 375 bead 16, blue tourmaline lepidolite reference bead 18, purple lepidolite 708 405 262 500 1000 Raman shift (cm-1) counts Raman spectra L' PT(=(Paraiba tourmaline L(=(Lepidolite L' L' L' PT' PT' PT'
Smoked Topaz !
Jewellery in the barbecue ??
Exceptional colour change garnet 140(ct
Member(of the pyrope(–(spessartine series with chromium and vanadium traces
Exceptional colour change garnet Colour change and(Usambara(effect(!!( Ruby'testing at'SSEF'
Ruby necklace of the Tsar…
Emerald(brooch(of(Queen(Marguerita(of(
This(brooch(is(actually(the(centreRpiece(
…and Queen Marguerita’s brooch
Savoy((1851R1926),(and(was(given(to(her( by(her(mother(the(Duchess(of(Genoa(at( the(occasion(of(her(marriage(to(Crown( Prince(Umberto(I(in(1868.(
of(her(emerald(necklace.( Quiz: 109 Emeralds, 6 grossularite garnets and one fluorite.
Pearls Beadless cultured pearls ( Still(in(the(market( The Swiss Gemmological Institute SSEF has been receiving large quantities of saltwater pearls for certification in recent weeks. These pearls are generally characterised by an almost perfect appearance. The pearls are often accompanied with reports describing them as natural pearls, but their appearance has raised doubt amongst many natural pearl dealers. Having tested these pearls with the most advanced technology, including X-ray radiography, X-ray lumines SSEF Newsletter May 2010 Trade Alert: “Keshi” cultured pearls are entering the natural pearl trade by Dr. Michael S. Krzemnicki, gemlab@ssef.ch cence, X-ray micro tomography and radiocarbon age dating (see Krzemnicki et al. 2009; or SSEF Facette No. 17, www.ssef.ch, news section), we see that many of these pearls are actu ally beadless cultured pearls. Fig. 2: Typical selection of these beadless cultured pearls from the Pinctada maxima (South Sea). © SSEF 2010 Fig 1: Necklace of beadless cultured pearls with an almost perfect and appealing appearance, tested recently at SSEF. © SSEF 2010 © Swiss Gemmological Institute SSEF, Newsletter May 2010 - page 1 The arrival of large quantities of these ,new’ saltwater pearls, whose quality is far better than that of many natu ral pearls treasured since centuries, represents a great danger to the natural pearl market. This especially because we have reliable infor mation, that some individuals are purposely selecting those cultured pearls with the most intriguing and potentially confusing internal structures (using radiography) from the large stocks they pur chase from pearl farms, so as to later introduce them onto the natural pearl market. Falknerstrasse 9 CH-4001 Basel Switzerland Tel. +41 61 262 06 40 Fax +41 61 262 06 41 gemlab@ssef.ch
Radiocarbon Dating of Pearls: © Swiss Gemmological Institute SSEF 1900( 1916( Mikimoto beaded saltwater cultured pearls Pinctada fucata Southern( Japan( 1960( beaded( saltwater( cultured( pearls.( Pinctada' maxima' Northern Australia( 1980(( beaded( saltwater( cultured( pearls.( Pinctada' margaritifera' French( Polynesia( Pre(1900( +irst( attemps( for(pearl( cultivation( (mostly( Mabé)(in( Japan,( Australia,( Europe( 1983( Chinese( beadless freshwater cultured pearls Unio 2001(„Keshi“( beadless saltwater cultured pearls enter trade(in(large( quantities Pinctada maxima 2009( saltwater cultured pearls with natural pearl beads Pinctada maxima 2000( Cultured(pearls(Market(share( Only(natural( pearls(in(the( trade( „the(bomb(peak“( athmospheric radiogenic 14C( Kim(Jong(Bumm ??( Recent shells: © Swiss Gemmological Institute SSEF OneSigma( [1959.61(Aug)(R(1959.81(Oct)](0.092576( [1989.67(Sep)(R(1992.10(Feb)](0.907424( TwoSigma( [1959.47(Jun)(R(1960.07(Jan)](0.118790( [1988.98(Dec)(R(1992.65(Aug)](0.881210( Note:(300(years(of(INTCAL04(data(have(been( prepended(to(this(data(set( Shell(from(Pinctada'maxima' (Silverlip'pearl'oyster)'from(the( Philippines,(collected(1990((pers.( comm.(H.A.(Hänni)( Calibration(of(1.162000±0.004000(with(SH1.14c(dataset( Smoothing:(1.000000( Q(Hua(and(M(Barbetti((2004)(Review(of(Tropospheric(Bomb(14C(Data(for(Carbon(Cycle(Modeling(and( Age(Calibration(Purposes,(Radiocarbon(46:(1273R1298(
Radiocarbon Dating of Pearls:
New cultured
product
Sample ETH-46319, a large pearl from Pinctada maxima (Fig. 3) - although declared being pre-1950 - reveals a historic age of 1623-1781AD (2 sigma probability). From the information of the collector, the measured 14C age is possible, but unfortunately not well documented. However, despite the unknown accuracy of the historic age, the age provided by the radiocarbon age determination allowed us in this specific case, to unambiguously identify the sample as a natural pearl, although previous testing with radiography and X-ray computed µ-tomography was not conclusive. The fact, that cultured pearls from maxima of such large size were only produced commercially after the “bomb peak” and the pre-bomb radiocarbon age helped to resolve the problem. For the seven more recent pearls and shell samples, which formed distinctly after the bomb-peak, the calculated and corrected radiocarbon ages are in four cases are quite well matching w 46324, ETH-46325, ETH-38493, ETH-46326), whereas (ETH-46327) with a declared age of 1982 and the two cultured 46320, ETH-46321) from 2009 reveal older ages. This again might indicate some variability in reservoir ages of this region that affects our results. Nevertheless, the pearls detect bomb 14C, which shows the potential of 14C for detection of this time marker.
Conclusions
This study has shown that radiocarbon age determination can provide additional and valuable information when testing pearls. We can distinguish two very different scopes. In the case of antique jewellery and treasures, age determination may support evidence for their historic provenance (e.g. sample ETH-46322). This can be of high importance, especially in the case of pearls of iconic significance in cultural history. A pearl set in a historic jewellery
© Swiss Gemmological Institute SSEF
Figure 4. Calibrated of ages of two historic pearls ETH-46322 and ETH-46323 that were formed before the bomb peak. Both pearls originate from the Arabian Gulf, and were calibrated using marine calibration curve INTCAL09 (Reimer et al. 2009) and R=190±180 yrs.
pearl
Large(baroqueRshaped( cultured(pearls(from(Tahiti( (Pinctada margaritifera),( partly(with(outstanding( orient.(
New cultured pearl product 1st generation
2nd generation
See(publication(in(the next Australian Gemmologist
Visit at Paspaley in North Australia
Peter(Bracher(from the Paspaley family(in(front(of the Paspaley(IV,(the main vessel,(on(which the grafting of(wild(shells is carried(out(
Harvesting a natural pearl from Pinctada maxima…
…and fishing in the Kimberleys
Thank you for your attention
© Swiss Gemmological Institute SSEF
