Tokki Pearls: Additional cultured pearls formed during pearl cultivation

1Swiss

Tokki Pearls:

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Additional cultured pearls formed during pearl cultivation: External and internal structures M.S. Krzemnicki1 , Mü ller2 , H.A. Hänn i3, H-P. Gut4, M. Düggelin5

Gemmological Institute SSEF, Basel, Switzerland, 2Hinata Trading Ltd., Kobe, Japan 3GemExpert, Switzerland 4Gloor 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 term to describe small „bumps“ (or additional cultured pearls) attached to a larger beaded cultured pearl.

Tokki pearl

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© Swiss Gemmological Institute SSEF We can distinguish three types of Tokki pearls: Type A with an irregular cavity connected to the bead of the larger cultured pearl Type B with an irregular cavity („ moustache“ ) surrounded by nacre Type C with a small additional cultured pearl ©

Swiss Gemmological

Institute

SSEF

Tokki pearl type A

X-ray computed microtomography (coronal sections):

Tokki

mxt 14b

3 © Swiss Gemmological

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SSEF

Models of Tokki pearl formation Tokki

Type A: bead mantle epithel

cavity nacre Tokki pearl type Aepithelium

“ bulging“grafting

nacre deposition First generation

Models of Tokki

pearl

formation Tokki

Type A: beaded CP incision cavity

due

to incision wound

Tokki pearl type A

first 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 matter Calcium carbonate aggregate organic rich matter due to a second hemorrhage into the pearl sac

Tokki pearl type B

Tokki No.

4 Transaxial microtomography sections Coronal microtomography sections

Tokki No.

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Models of Tokki pearl formation

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© Swiss Gemmological Institute SSEF Tokki Type B: Small tissue piece „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 tissues become one First generation ©

Swiss Gemmological

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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 and dense 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

No. 22 loose nacre layers latest nacre layer

Soap

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bubbles.... © Swiss Gemmological Institute SSEF Models of Tokki pearl formation Tokki Type C: tiny tissue piece CaCO3 „spot“ tissue „wrapping“ and nacre cover Tokki pearl type C conchioline-rich layers grafting formation of independent additional CP docking of additional CP on beaded CP Two tissues become one First generation

Pertinence

for pearl testing Additional cultured pearl formation: tiny tissue piece CaCO3 „spot“ Additional cultured pearl grafting formation of independent additional CP additional CP remains loose First generation © Swiss Gemmological Institute SSEF Pertinence for pearl testing mxt61_20

Pertinence for pearl testing

Natural or cultured pearls ?

Pertinence for pearl testing

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Photo & Radiography © GPTL Bahrain Loose ring structures (conchioline-rich) whitish „globuli“ former „docking“ feature of Tokki pearl to larger beaded CP pearl Photo & Radiography © GPTL Bahrain

Pertinence for pearl testing

Conclusions

Tokki pearls are a by-product of pearl cultivation

We distinguish three types of tokki pearls ( cultured pearls) depending on their internal structures.

Tokki pearls may fall from the larger cultured pearl during harvesting or even not attach to the cultured pearl at all; thus be present as loose additional cultured pearl!

Tokki pearls (and additional cultured pearls) generally are characterised by loose ring structures, distinct drying fissures , a calcium carbonate central core surrounded by organic-rich layers , and often irregularly distributed small calcium carbonate spheres ( „globuli“)

Using radiography and microtomography, Tokki pearls and additional cultured pearls can be detected.

Swiss Gemmological

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©

Institute SSEF

Thank you for your attention

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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

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