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Baltic Amber - Autoclave Treatment

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Pertaining to various threads recently about insect inclusions in Baltic amber and the possibilities for faking, I thought you may be interested in the attached paper. It’s not widely known in the fossil community that the sellers of this material (especially those in the jewellery trade) have for many years been autoclaving the material to improve its colour and clarity. An autoclave is a steam oven that functions a bit like a large pressure cooker, typically used in hospitals for sterilizing surgical instruments.

One of the spin-offs from this practice is that there has been a dramatic increase in the availability of Baltic material containing insects reaching the fossil community because it is now being widely applied to cheaper (and often younger) layered amber. This extract from Christel Hoffeins’ paper (published last year):

“The prices for trade quantities of amber have increased year by year, so many companies have started to treat large quantities of the so-called “Schlauben” or “sklejka”, a cheaper quality of raw layered amber.

Layered amber was formed by successive resin flows outside the bark of the amber tree, sometimes up to 100 in large samples, and the surface of each layer was as sticky as flypaper. The percentage of inclusions is higher than normally found in unlayered amber pieces. Schlauben are very brittle and cannot be cut for beads or other products. But after treatment in an autoclave the layers are permanently bound, and can then be cut and trimmed without difficulty or loss of prized material.

A side-effect of clarifying and Schlauben processing is the large amount of autoclaved inclusion material available on the market.”

The paper describes the process, what happens to the amber and what happens to the inclusions with some interesting comment of the difficulties this may create for insect identification in specimens that have been purchased rather than found.

Baltic Amber - Autoclave Treatment & Effect on Insect Inclusions.pdf

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Very interesting :) thanks for sharing!

I remember the year that in Poland the communist system ended by the actions of "Solidariteit/ Solidarnosc" (4 june first free democratic selection).

In september that year the first people from Poland appeared on the fossil and mineral fairs with huge quantities of amber with very high quality!

The traders weren't used to the prizes of amber in "the west". And they first months they sold for very low prizes.

In one case I experienced that a dutch dealer bought the entire stock (and that was a big stock:)) in one minute.

After a few more month the prizes skyrocketed :(


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Hi Painshill,

Great paper! There are some excellent reference photos in there as well. :)

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