From the Bench: Making Things Amber Clear

This post is part of the “From the Bench” series celebrating the work of conservators. Part scientist, part detective, they work to preserve the past for the future. This series features the voices of conservators who are working on IMLS-supported projects in museums across the United States. For more information about IMLS funding for museums see www.imls.gov/applicants/available_grants.aspx.

Elizabeth Nunan, Associate Conservator, American Museum of Natural History, Natural Science Collections

With funding from the IMLS Conservation Project Support grant program, the American Museum of Natural History (AMNH) conservators and fossil preparators have spent the past 12 months treating and documenting the museum’s unique and global collection of fossils in amber. The AMNH amber collection is one of the world’s largest, most diverse, and scientifically significant with nearly 17,000 pieces containing well over 25,000 inclusions of insects and other ancient life forms. When exposed to ambient conditions, such as light, temperature, and relative humidity, amber darkens, and over time microscopic cracks can form on exposed surfaces. In severe cases, this network of cracks, or crazing, can completely mask the inclusion, and large fractures can extend through their bodies. Without treatment, the amber can break or crumble, exposing the inclusions to further deterioration and making the specimen unsafe to handle or study. The IMLS Amber Fossil Conservation project was designed to stabilize all of the most scientifically important and some of the most deteriorated pieces in this collection so they can be safely stored, handled, and preserved for future research and exhibition. Of particular concern was treatment of the scientifically important type specimens – the first specimen to which the scientific name of an organism is attached.

Images of amber with insects before and after treatment

Before and after images show how treatment minimized cracks and crazing in the amber

To prevent the darkening and crazing that obscures and damages inclusions each amber type specimen is treated with Epo-Tek 301-2 epoxy,  either by coating exposed surfaces or embedding whole pieces under vacuum.  Embedding the amber in epoxy stabilizes the specimen by infiltrating the cracks, and making it less likely to break during trimming and polishing. One of the key benefits of such preparation is that researchers can get much closer to the inclusion and gain clearer views of important characteristics, without risking breakage or internal cracking. Many fossil insect specimens in amber could never have been properly studied without this process.

This project has helped ensure the preservation and overall accessibility of the museum’s priceless amber collections for the benefit of generations to come. In addition, the AMNH has already shared lessons learned and procedures developed with other institutions through publications and lectures at professional conferences such as the Society for Preservation of Natural History Collections, the International Paleoentomological Society, the Paleontological Society of India, and the University of Lucknow, India.

 

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