Assessing the prevalence of glass alteration in natural history collection specimen storage

Glass plays a large role in the storage and preservation of natural history collections, from the jars and vials used to preserve specimens in fluid to the glass microscope slides holding thin sections and fragments. While the glass used for storing specimens is typically not considered part of the collection it houses, the condition and preservation of the glass directly impacts the long-term preservation of the collections as well as the time and budgetary resources of the museum. This is particularly true for large collections where consistent monitoring of the condition of every item is not realistic. The Glass Deterioration Working Group at the Smithsonian Institution conducted a survey of the condition of the fluid collections and microscope slides in the Department of Invertebrate Zoology at the Smithsonian Institution’s National Museum of Natural History. Nearly a third of microscope slides, and over half of fluid collection containers were observed to have visible indications of glass deterioration.