Is Amber Decomposing over Time?

By Adam Spiegel

In the city of Oaxaca ("wa-haka"), Mexico, in the State of Oaxaca, one can visit the Regional Museum. It is a large and beautiful building filled with pre-Columbian art and artifacts. Housed in a convent which dates from the 16th or 17th Century, it is one of the finest museums in Mexico.

There are artifacts from all over the Republic on display in this museum, but it is especially strong in artifacts of the ancient civilizations which occupied and flourished in the Valley of Oaxaca, an area rich in pre-Columbian archaeological sites.

Probably the most well known and largest such site sits on a mountain just outside the city limits. This is the site of Monte Alban. Beginning around 800 BC, and until about 800 AD, the Zapotecs leveled the top of this mountain and built their ceremonial plazas and temples. Several hundred years later, around 1200 AD, the Mixtecs moved into the valley and occupied the then vacated Monte Alban, using it for their own purposes.

Archaeological investigations at Monte Alban uncovered a treasure of beautifully worked gold and semi-precious stones in what is known as Tomb 7. One of the exhibits in the Regional Museum contains objects found in this tomb. The Tomb 7 treasure was Mixtec in origin; the Mixteca people were great goldsmiths and lapidaries. Part of the treasure is objects worked in amber. These objects were created between 650 and 900 years ago. Undoubtedly the amber came from the State of Chiapas, which is just to the east of the State of Oaxaca.

There is a special room in the museum where the objects from Tomb 7 are exhibited. One walks from the bright lights of the other exhibit halls into the gloomy darkness of the Tomb 7 display room. The theatrical effect does the trick, for out of the gloom shines forth delicately wrought objects in gold, amber, turquoise and jade. I feel that this room is kept dark merely in order to show off the objects better, and to also create a feeling of being in the tomb where they were found.

Some writers say that amber needs to be protected in order that it not decompose after exposure to the air. It is well known that beads and other objects made from Baltic amber sometimes change in color and have perhaps crazed over time, that time scale being from 100 years in the case of some red Victorian amber necklaces, to 5000 years in the case of Neolithic amber objects. It is possible that the lighting in the Tomb 7 treasure room is kept low so as to not hasten deterioration of the objects, especially those made from amber, but I do not know this for a fact. Similarly, I do not think that the cases are air tight. However, it would be interesting to know if in fact the museum curators have indeed designed the exhibit in order to minimize or prevent deterioration of the amber artifacts.

I have been selling Chiapan amber for 15 years. It is the only kind of amber I sell. I go directly to Chiapas on buying trips and over the years have developed a network of people from which I hand select the best stones. In all that time I like to think I have become familiar with the amber regions of Chiapas and how the amber business is conducted in those areas. Every time I go I make more contacts, explore further, and learn more. Yet in 15 years I have never heard of Chiapan amber decomposing over time. If it does, it would take a very long period of time for this to occur. None of my pieces have ever changed color or decomposed, and none of my clients have ever told me of that happening to their pieces.

Some writers also say that Superglue is used during polishing of Chiapan amber in order to prevent decomposition of the pieces upon exposure to air, especially the red amber. In my experience, Superglue is sometimes used in order to stabilize surface fractures while the piece is worked, not to prevent a piece from total decomposition. Certainly a lot of the red rough amber is crusty and falls apart to powder, but that is why good polished pieces are rare and getting more expensive every day. The red rough is NOT infused with superglue, resins, hardeners, epoxies or anything else in order to be able to work it. If the piece doesn't hold up to being worked and polished without artificial fillers or treatment, it is discarded.

Attached to this article is a photo of genuine, untreated, polished Chiapan red amber currently in my inventory, and a photo of a large piece of semi-polished red rough which I sold to a collector. In the one photo it can be seen that the color balance is correct because the US one cent piece is in the photo for comparison. The photos were taken in front of a window with natural sunlight. No photo manipulation was used in making the photos.

I will be going to Chiapas again in the near future. I will ask my contacts about all this talk about decomposition. It is an interesting topic for discussion. Certainly there are many objects made from amber in the world's museums and in private collections. Many of these pieces have been out of the ground and exposed to air for hundreds, if not thousands, of years. In some cases preventive measures may be in order to prevent crazing and the need for re-polishing pieces. In other cases it may not be necessary to do anything. In the meantime, the Mixtec amber treasure from Tomb 7 of Monte Alban is intact after 800 years, and is a reminder that the beauty of amber shines from the ancient past into the present day.

The above text and photos were copyrighted 2006 by Adam Spiegel.  You can contact the author at spiegela@prodigy.net