IGC2011 MSK print - SSEF · We distinguish three types of tokki pearls (cultured pearls) depending...
Transcript of IGC2011 MSK print - SSEF · We distinguish three types of tokki pearls (cultured pearls) depending...
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Tokki Pearls:
Additional cultured pearlsformed during pearl cultivation:External and internal structures
M.S. Krzemnicki1,Müller2,
H.A. Hänni3,H-P. Gut4,
M. Düggelin5
1Swiss Gemmological Institute SSEF, Basel, Switzerland,2Hinata Trading Ltd., Kobe, Japan
3GemExpert, Switzerland4Gloor Instruments, Uster, Switzerland
5Centre for Microscopy, University Basel, Switzerland
32th IGC Conference, July 2011
Interlaken
Tokki pearl
© Swiss Gemmological Institute SSEF
“Tokki”is a Japanese termto describe small„bumps“(or additionalcultured pearls)attached toa larger beadedcultured pearl.
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Tokki pearl
© Swiss Gemmological Institute SSEF
We can distinguish three types of Tokki pearls:
Type Awith an irregular cavity
connected to the bead ofthe larger cultured pearl
Type Bwith an irregular cavity
(„moustache“)surrounded by nacre
Type Cwith a small additional
cultured pearl
© Swiss Gemmological Institute SSEF
Tokki pearl type A
X-ray computed microtomography (coronal sections): Tokki mxt 14b
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© Swiss Gemmological Institute SSEF
Models of Tokki pearl formation
Tokki Type A:
bead
mantle epithel cavity nacre
Tokki pearl type Aepithelium “bulging“grafting nacre deposition
First generation
© Swiss Gemmological Institute SSEF
Models of Tokki pearl formation
Tokki Type A:
beaded CP
incision
cavity due to incision wound
Tokki pearl type Afirst harvest nacre deposition
Second generation
bead for 2nd generation CP
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Tokki pearl type B
Tokki No. 3
© Swiss Gemmological Institute SSEF
SEM micrograph
Tokki pearl type B
nacre
organic rich matter
Calcium carbonate aggregates („globuli“)
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Tokki 24
nacre
nacre
organic rich matterCalcium
carbonateaggregate
organic rich matterdue to a second
hemorrhage into thepearl sac
© Swiss Gemmological Institute SSEF
Tokki pearl type B
Tokki No. 4
Transaxial microtomography sections Coronal microtomography sections
Tokki No. 7
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© Swiss Gemmological Institute SSEF
Models of Tokki pearl formation
Tokki Type B:
Smalltissuepiece
„moustache“
tissue „wrapping“and nacre cover
Tokki pearl type B
„folding“
grafting
formation of independent beadless CP
docking of beadless CP
on beaded CP
Two tissuesbecome one
First generation
© Swiss Gemmological Institute SSEF
Tokki pearl type C
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Tokki No. 19
Tokki pearl type C
nacre
Loose ring structures(rich in organic matter)
Large drying fissures
Whitish layered CaCO3 „globuli“ interlayed in conchioline
© www.homoeopathie-allenstein.de
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Tokki No. 13b
organic-rich layer
Large core with fine-porous anddense columnar intergrowth of
CaCO3
nacre
© Swiss Gemmological Institute SSEF
Tokki No. 10 transaxial sections
Tokki pearl type C
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© Swiss Gemmological Institute SSEF
Tokki No. 15, coronal sections
Tokki pearl type C
Tokki No. 22loose nacre layers
drying fissures
latest nacre layer
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Soap bubbles....
© Swiss Gemmological Institute SSEF
Models of Tokki pearl formation
Tokki Type C:
tinytissuepiece
CaCO3 „spot“
tissue „wrapping“and nacre cover
Tokki pearl type C
conchioline-rich layers
grafting
formation of independent additional CP
docking of additional CPon beaded CP
Two tissuesbecome one
First generation
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© Swiss Gemmological Institute SSEF
Pertinence for pearl testing
Additional cultured pearl formation:
tinytissuepiece
CaCO3 „spot“
Additional cultured pearl
grafting
formation of independent additional CP
additional CPremains loose
First generation
© Swiss Gemmological Institute SSEF
Pertinence for pearl testing
Detection of additional cultured pearls !
mxt61_20
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Photo & Radiography © GPTL Bahrain
Pertinence for pearl testing
Natural or cultured pearls ?
Pertinence for pearl testing
Loose ring structures (conchioline-rich)
whitish „globuli“
former „docking“ featureof Tokki pearl to largerbeaded CP pearl
Photo & Radiography © GPTL Bahrain
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© Swiss Gemmological Institute SSEF
Pertinence for pearl testing
mxt61_20
whitish globuli
White CaCO3 central spot
Additional cultured pearls:
Photo & Radiography © GPTL Bahrain
ConclusionsTokki pearls are a by-product of pearl cultivation
We distinguish three types of tokki pearls (cultured pearls) depending ontheir internal structures.
Tokki pearls may fall from the larger cultured pearl during harvesting oreven not attach to the cultured pearl at all; thus be present as looseadditional cultured pearl!
Tokki pearls (and additional cultured pearls) generally are characterised byloose ring structures, distinct drying fissures, a calcium carbonate centralcore surrounded by organic-rich layers, and often irregularly distributedsmall calcium carbonate spheres („globuli“)
Using radiography and microtomography, Tokki pearls and additionalcultured pearls can be detected.
© Swiss Gemmological Institute SSEF
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Acknowledgements:- Andy Müller for the donation of many cultured pearl samples- Sam Buchanan for comments and discussions- Dr. Franz Herzog and Piotr Halicki for many pearl radiographies- Ali Safar and Abeer Al Alawi from the Bahrain Pearl and Gemstone Testing Laboratory for radiographies and fruitful discussions
Thank you for your attention