From classic inclusions to neutrons:
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A ‘fresh’ look at modern gemmology PD Dr.Michael S. Krzemnicki, Swiss Gemmological Institute SSEF www.ssef.ch Photos © M.S. Krzemnickiand SSEF, except where indicated otherwise The ‚Ratnaraj‘ Ruby, 10.05 ct, soldatChristie‘sHK december2016
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MogokGemstone Tract
FromGeologyto Gemmology
MogokGemstone Tract
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From Geology to Gemmology SimplifiedgeologicalmapfromKhinZaw et al. 2014 Metamorphic rocks (mainly marbles and gneisses) closely in contact with magmatic rocks (mainly granite and syenite). SGG Zermatt 30th June 2017 | Page 5 Inclusion paragenesis From Geology to Gemmology Inclusionsuitein rubyfromMogok
Inclusion paragenesis
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Inclusion studies gypsum or anhydrite dolomite calcite dolomite dolomite mixture of Na, Mg, F neighborite(NaMgF3) ? mica apatite apatite calcite dolomite What microscopically looks as one inclusion is quite often a mixture (intergrowth) of several mineral phases.
Photos: PhDcand. MyintMyaPhyo, SSEF
SGG Zermatt 30th June 2017 | Page 7 BaddeleyiteZrO2 Inclusion studies -10000 10000 30000 50000 70000 90000 110000 10030050070090011001300 Counts Raman Schift (cm-1) Tiny baddeleyite(ZrO2) as accessory inclusions indicate magmatic contribution to gemstone formation in metamorphic marbles. Figures: PhD cand. Myint Mya Phyo, SSEF Raman spectrum of baddeleyite ZrO2 baddeleyite Baddeleyite in spinel from Mogok
Inclusion studies
Zircon
Age dating of zircon inclusions
Granitoidzircon
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zircon zircon TiO2 zircon rutile rutile corundum
Photos: PhDcand. MyintMyaPhyo, SSEF
Pink sapphirefromMogok
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GemTOF
(zoned) Figure (modified) from Chew et al. 2017
inclusions (at the surface) enable us to carry out U-Pbage dating of gemstones, using the GemTOF(LA-ICP-TOF-MS). Zircon at girdle of sapphire Figure H.A.O. Wang, SSEF 2016 WH1
WH1 A new figure is attached, including two analyses of Zircons on SriLanka and kasmir sapphires. Wang, Hao; 25.09.2017
Slide 10
Inclusion studies
Zircon ZrSiO4
Zircon in pink sapphire from Ilakaka, Madagascar
heated 800°C heated 1000°C
unheated heated 400°C
Raman spectra show the effect of heat treatment on the cristallinity of zircon inclusions in pink sapphires (from Ilakaka, Madagascar).
increaseheating
Inclusion studies
Zircon ZrSiO4
High-temperature heating results in melting of zircon and precipitation of baddeleyite in silica glass matrix
reference baddeleyiteZrO2 heated 1800°
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Inclusion studies
7
dendritic baddeleyiteZrO2 precipitates within silica glass matrix (amorphous) on the surface of beryllium diffusion treated corundum.
HRTEM picture Nasdala et al. 2009
baddeleyite Si-glass (amorphous)
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tiny prismatic zircon inclusions in sapphires from Bemaintynear Ambatondrazaka (Madagascar), visually quite similar to zircons in Kashmir sapphire
prismatic zircon inclusions in Kashmir sapphires, often slightly corroded.
Kashmir Ambatondrazaka, Madagascar
Inclusion studies
Raman
Kashmir
non-metamictzirconinclusions
metamictzirconinclusions
‚Kashmir-like‘ sapphires of
Inclusion studies
Analysis
from
at Bemaintynear Ambatondrazaka, Madagascar.
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spectra of zircon inclusions
excellent quality
new deposit
Ambatondrazaka Madagascar
SGG Zermatt 30th June 2017 | Page 15 0.00 5.00 10.00 15.00 20.00 25.00 1005 1010 1015 1020 FWHM Raman peak (Raman shi wavenumber cm-1) Zircon ZrSiO4
increase in metamictisation Raman peak at ~ 1008 cm-1, anti-symmetric ν3 (SiO4) stretching: Mogok, Burma Madagascar Sri Lanka Umba, Tanzania Kashmir Mercaderes, Colombia
of Raman spectra (position and peak width of 1008 cm-1 peak) of zircon inclusions of corundum (ruby/sapphire) specimens from different origins.
9 SGG Zermatt 30th June 2017 | Page 16 Time ofFlight : GemTOF New instrument NWR193UC ESI icpTOF TOFWERK AG iCAPQc ThermoFischer SGG Zermatt 30th June 2017 | Page 17 Basic principle of laser ablation ICP mass spectrometry at surface using pulsed laser of high energy by carrier gas (e.g. helium) in inductively coupled argon plasma (ICP) of singly charged isotopes (and some complexes) two main principles Material ablation Transport of particles Ionisation of particles Injection
into
mass spectrometer Mass separation
Isotope/mass detection
magnetic field e.g. quadrupole time
of flight of
isotopes
New
Time ofFlight : GemTOF
New Instrument
Time ofFlight : GemTOF
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instrument SGG Zermatt 30th June 2017 | Page 19
Inclusion studies
Kashmir sapphire
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The Richelieu sapphires, soldatSotheby‘s Geneva forUS$ 8.35 mio.
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Pargasite(amphibole) in sapphire from Kashmir
FromGeologyto Gemmology
Corundum from amphibolite faciesrocks
FromGeologyto Gemmology
Corundum from amphibolite faciesrocks
Rubies from amphibolite (metamorphic rock) are characterised by a distinct iron concentration, thus contributing to their colour and UV fluorescence reaction.
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Ruby in amphibolite from Montepuez, Mozambique
Photo: H.A. Hänni, SSEF
Simonet et al., 2008
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Amphibole in ruby
Inclusion studies
Amphibole in ruby
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Zermatt 30th June 2017 | Page 24
Inclusion studies
Montepuez, Mozambique Montepuez, Mozambique
Didy, Madagascar Andilamena, Madagascar
SGG
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Ruby, fancy sapphires (ruby-sapphire mix) and sapphires from Winza, near Dodoma (Tanzania).
Inclusion
Amphibole in ruby
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studies local change of the Ti4+ -Fe2+ intervalencecharge transfer (IVCT) presumably caused by a reaction with the amphibole inclusion results in spericalcolour „hole“ around these amphiboles. 1 0 0 0 0 ruby ruby ruby zoning zoning blue blue blue blue blue 3 5 8 10 1 2 3 4 56 7 8 910 1000 100 10 1 Log concentration[ppm] LA-ICP-Q-MS Ti Fe Cr Mg Ga V SGG Zermatt 30th June 2017 | Page 27 Amphibole in emerald Inclusion studies X-rayµ-tomographysection actinolite-tremoliteneedles Raman spectrum Emerald sample –LABc_1144 Sandawana(Zimbabwe)
15 SGG Zermatt 30th June 2017 | Page 28 Using Neutrons and X-rays (PSI) Inclusion studies 0 50000 100000 150000 200000 250000 300000 350000 400000 0 200 400 600 800 1000 1200 1400 1600 LABc_1209_Colombia_surface LABc_1209_Colombia_resin artificial resin emerald surface NeutronCT X-rayCT 1608 cm -1 1445 cm -1 3D visualisation of inclusions and organic fillers in emeralds Project in collaboration with the Laboratory forNeutron ScatteringandImaging atPSI Colombian Emerald NeutronCT SGG Zermatt 30th June 2017 | Page 29 Using neutrons and X-rays (PSI) Inclusion studies Neutronµ-tomographyX-rayµ-tomography Neutronµ-tomographysectionX-rayµ-tomographysection White=±notseen=cavityfilling(epoxy) Grey=white=pyrite Black=black=cavity Weakgreyishlines=notseen=fissurefilling(epoxy) ±notseen=grey=calcite Emerald sample –LABc_1209Colombia
Conclusions
Inclusions in gemstones are highly important clues for a better understanding of (coloured) gemstones.
They reveal important information about formation processes, geological setting, and treatments.
The analysis of gemstones and their inclusions is based on a large range of methods from basic microscopy to advanced methods using laser light, X-rays, electrons and neutrons.
The aim is to characterize their chemical, isotopic, and structural state as far as possible.
Until today, meticulous microscopic examination of gemstones and their inclusions remains crucial, as it not only unveils their beauty, but also provides a wealth of information to gemmologists.
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SGG Zermatt 30th June 2017 | Page 31 Thankyoufor yourattention swiss-image.ch_AndreasGerth
