Sumatran Blue Amber: Why Some Fossil Resin Glows Under UV

Amber is fossilized tree resin, and some material from Sumatra is especially sought after because it can show striking blue fluorescence under ultraviolet light.

Why blue fluorescence happens

The effect comes from organic compounds within the amber that absorb ultraviolet energy and re-emit visible light. The apparent color can vary with UV wavelength, specimen thickness and surface condition.

Our 6.9 oz example

The Hidden Bazaar currently has a substantial one-of-a-kind Sumatran amber specimen weighing 6.9 oz that shows blue fluorescence under UV.

View the Sumatran fluorescent amber specimen.

What to evaluate

Collectors should compare normal-light appearance, fluorescence strength, transparency, internal features, weight and provenance rather than judging only by glow.

See more fluorescent specimens.