What happens when heating amber chunks in an oven

In 2004, my girlfriend wife and I went on holidays to Lithuania. Among other places, we visited Klaipeda (Memel) to spend a few days at the Curonian Spit (Kurische Nehrung). It is a famous UNESCO world heritage site. We were lucky, the Baltic Sea was rough and during a morning walk we discovered something glittering in the seaweed: Amber chunks.

In Klaipeda, street vendors offered pretty much any kind of amber “collectibles”. Most of them were counterfeits in egg-shape, with inclusions of wasps or scorpions. But they also had really nice jewelry made of processed amber. A friendly vendor described the manufacturing process: Most amber findings have a milky white or yellow color. They are too shabby for jewelry. These chunks are carefully cooked in sand to gain a clear honey-like color. Back from our vacation, I had to try this out. 🙂

The first picture shows a few pieces of yellow amber, lying on baking paper. They have a diameter of about 3-5 millimeters.After half an hour at about 250°C their color noticeably changed to the typical brown.After an hour their tone was even darker, but did not significantly change anymore.