Strack presents for AGTA at Tucson Gem Show

[Caitlin]

This is a free seminar limited only by available seating. anyone have Questions?

http://www.agta.org/consumer/tradeshows/gfseminars.htm

Saturday, February 3, 2007

Treatment and Artificial Coloration of Pearls
(Mohave Room, 9:00 a.m. – 10:00 a.m.)
Elisabeth Strack, Gemmologisches Institut Hamburg, Germany. Intermediate - Advanced. Challenge your top sales people with in-depth information regarding ever increasing quantities, and treated and artificial colored pearls which are coming onto the market. Understand when and what type of treatments and artificial dyeing are applied. Learn about recent markets, what might need extra caution, what observations are necessary and when to get professional help. Strack offers a detailed overview on techniques applied for changing the outward appearance and color of cultured pearls and also concentrates on how far the naked eye and standard gemological testing methods can be used to detect treatments and artificial coloration. PowerPoint.​

 

[effisk]

anyone have Questions?

when does it happen in Paris?

More seriously, any chance for a video recording?

 

[Caitlin]

Photos and suchlike are strictly prohibited at this gem show. I imagine a few reporter types get limited special privileges. I have thought of trying to pass as a reporter, but have not come up with a good plan, yet.

 

[judimcc6]

AGTA seminar

AGTA seminar

Caitlin,

Thanks for the heads up on the seminar. I was at the AGTA show yesterday and will be at the seminar tomorrow! There really seems to be an over abundance of pearls this year...of all qualities. AGTA is making a reall effort to educate all buyers of the enhancements of a lot of the pearls on the market now. Knowledge is power.

 

[Caitlin]

Hi Judi
Great! Make yourself known.

 

[judimcc6]

Great seminar

Great seminar

Caitlin,

yes, it was a great seminar, once the sound was stabilized. I have known that Srack's book on Pearls is the definitive book and it was extra special to meet her. She has a very real workable sense of how one can detect (or, at least ask the questions) various treatments to pearls without expensive equipment. I went back to the shows with intelligent questions for some of my suppliers. I am just sorry I missed meeting you. I looked for you, but couldn't read all the name tags. There were so many people crwoding around her after the seminar that I slid out after about 10 minutes...anxious to go ask questions. Again, thanks for the information.

Judi

 

[pattye]

CAITLIN!

Excitedly awaiting your report on this day's events!


Patricia Saab

 

[jshepherd]

The seminar was good. But if you have the Strack book you would have recognized a rehash of her treatment section. There were a few new things near the end, however, that she had not included in the book.

It was a good time. I was lucky enough to talk with Strack for a good 30 - 45 minutes after the crowd had left (she was amazed by the Freshadama that I had brought). I sat near the front next to Caitlin and her daughter. Bo Torrey, Stephen Bloom, Douglas Fiske, Jeremy Norris, PearlGully from the forum, Lois Berger, and so many more were there. After the seminar a group of us did another "unofficial" pearl walk which lasted until we were kicked out and the lights were turned off. That was followed by a pearl history discussion over dinner at the Signature Room, and completed with a Chinese pearl farm tour itnerary building party for Stephen Bloom in the lounge.

7:00am out of the room - back in by 11pm. A long day, but definitely worth it!

 

[pattye]

Thanks sooo much, Jeremy,

I am studying the Strack book, bought it for myself for Christmas! Thanks for taking time from your day to report back, and hope we will hear more when you catch your breath.

Pattye

 

[Caitlin]

Hi Folks.
Jeremy certainly gave you a good break down of our schedule. It was so much fun and so educational to hear all the experts chatting. I was in pearl paradise (no pun intended, ha ha) for 14 hours, nothing but pearl talk!

For those who do not have Strack's book a brief description of her speech highlights will follow later today. I vividly remember just about everytrhing she said and there were big power point pictures with the important points on them.

More people than Strack were impressed by Jeremy's freshadamas. He left 5-6 of them on a table while he was talking with Strack and I was able to give a B&M jeweler who LOVED them a quick pearls 101. And from the prices we saw yesterday, this jeweler, or any other jeweler in the know, would be better off ordering RETAIL from Jeremy and reselling it at double or triple, than buying from any of the so-called wholesalers at this show!

Make no mistake there were some LOVELY pearls there, they were all just astronomically priced! I will share some examples in another post- there is just so much to say........

 

[Caitlin]

Elisabeth Strack?s AGTA lecture 2/3/07 Lecture
Treatment and Artificial Coloration of Pearls

First Ms Strank said that disclosure is necessary for full confidence and that some pearl treatments do not need to be disclosed and referred to the required disclosures lists in the CIBJO Pearl Book. In short, bleaching, polishing, and pink tinting that can?t be detected are allowed without disclosure. She described the typical bleaching and polishing methods.

A typical bleaching is done with weak H2O2 solutions and some mild heat for periods of time, until the pearls are an even color. It is the organic layers of the pearl that are affected by the bleach. Pinking is done with a mild solution of coloring agent and may take 60 days. It does not have to be disclosed if you can?t see any evidence of it left behind, especially around the drill hole She showed slides to demonstrate examples.

After bleaching and pinking comes polishing with is done by tumbling the pearls with cork, walnut shells, even micro diamond dust.

She then made some statements about over-treatment. She almost said this quote from her book, verbatim, so I will use it here, ?All white akoya pearls marketed today have been processed. Even lower qualities with a thin nacre thickness can be treated so perfectly that the original quality can no longer be recognized, even by the expert.? (Strack, 2006 p 650)

She goes on to say that these over-treatments on thinner nacre result in pearls that ?change their appearance within a year, even if they are kept in storage? (p 651)

Dying and other treatment should always be disclosed, but often, they are not. She named many methods for dying and artificial colors. She said hair dye products color pearls. Silver nitrate salts seems to be the primary dye for black pearls. She described it and said it is used in akoya, cfwp, and Tahitians. To detect this dye, she says that a strong light source will make pearls dyed with this, look brownish. She also said to check for uneven distribution as in pinking and especially, lack of pigment in dimpled areas making white spots.

She gave a description of dying processes which result in yellow and gold colors. Tips in recognizing these dyes included some shots ?finger prints seen just below the surfaceof a spidery lines that look lighter than the surrounding areas when you look closely into the surface.

Waxes and other more permanent finishes such as polymer resins were outlined. These coating increase surface luster and will wear off. They can be detected by a couple of simple tests, such as a poke with a pin. In a polymer coated pearl, the pin will go into the surface, which it can?t do if there is no plastic coating.

 

[DFrey]

Hi Caitlin,Judi, Jeremy,
great to hear the reports from Tuscon wish I could have been there for the lecture and the show. First what is the CIBJO Pearl Book?
Is it possible to detect dye treatment on pearls using a simple cotton swap with alcohol, as it is with some gem stones?

Judi , if you wouldn't mind sharing what are some of the questions you will ask your pearl suppliers about their pearls that you weren't asking before attending the lecture?

Thanks
Dfrey

 

[judimcc6]

It was great to see her pictures (when they were in focus) enlarged so much on the power point screen. I would have liked it if she had had a question and answer time. And, dang, Jeremy, I would have loved to have seen your freshadamas in person. I was ony sitting 2 rows back from you and Caitlin, I think. I am sorry that I missed meeting all of you. It would have been my treat.

Caitlin, I am glad that you thought the prices for pearls was quite high. There also seemed to be such a gap in quality between the South Seas and the lower end CFWPs. I didn't see many in the larger 13-14mm range, either. I am just so glad that I made some good purchases in China.

 

[pattye]

Hi judimcc6,

I recall you asked questions before going to China, but I don't recall
if you told us what you found in large pearls, and how the bartering went! I recall Jeremy gave you some tips on how to and who to see. Hope you can share!

Thanks very much,

Pattye

 

[judimcc6]

Dfrey,

The CIBJO book is published by the World Jewellry Confederation and by their opening introduction...

The CIBJO Blue Book is a definitive set of standards for the grading, methodology and nomenclature standards for diamonds, coloured gemstones and pearls, in which the latter incorporates all organic materials. It was initially compiled, and since has been consistently updated, by number of committees, comprised of representatives from trade organizations and laboratories in the diamond, coloured gemstone, cultured pearl and jewellery industries. The standards represented a consensus derived from the broad expertise on the subject within these committees, and also from individuals outside the committees who had expressed an interest in participating in the development of the guidelines.

You had asked what questions I now ask any prospective suppliers. In addition to asking if their pearls had had any treataments, I would ask about specific treatments, such as dyeing, polymer coating, silver nitrates, and of course, irradiation. Someone in the audience asked if there was any residual radiation left in pearls and Ms. Strack said, absolutely not. It was one of those questions that I didn't really know the answer to and I am glad I know the answer now.

It's always good to be in the company of people that know so much about the things I am interested in. Besides, it was cold in Vermont!

 

[effisk]

Hi all,

is that blue book available online?

 

[effisk]

Caitlin,

thanks a lot for your summary. I definitely need that book. Should get it tomorrow.

 

[Caitlin]

Hi fx
Anyone who wants to learn about pearls can learn far more than the current GIA pearl course with just this book. And for about $100 plus $36 shipping from Germany (It weighs a few pounds!) it is far less expensive that the GIA course.

It will do until the GIA updates its course and uses this book to do it!

 

[Caitlin]

http://www.cibjo.org/bluebook.html

Try this link

 

[effisk]

http://www.cibjo.org/bluebook.html

Try this link

thanks. I emailed them.

I am buying the strack paving stone from the french gemmological association tomorrow.