Textile Pseudomorphs from a 17Th-Century Native American Burial Site

Cathy J. Coho
Textile Conservator.
Chicago Conservation Center
Chicago, IL

February 21, 1997

Fragments of physically altered textiles often have been found in archaeological setting or on museum artifacts retrieved from burial environments. Pseudomorphs, mineralized textile formations result from specific reactions between fibers, metals, and components in the burial environment. Positive pseudomorphs are formed by replacement of the organic elements by mineral compounds; negative pseudomorphs are formed as metal impressions of fibers before they completely decayed. Textile remains from a 17th-century Narragansett Indian burial site in Rhode Island were found in both extant and mineralized forms. Selected mineralized wool textile fragments were examined physically and chemically Mineralized textiles usually formed on iron and copper artifacts, but also were observed with the stereo microscope on non-metallic surfaces such as reed matting and wood. SEM was used to document examples of both types of pseudomorphs. Elemental analysis with EDS and XRD were used to determine the elemental composition of the mineralized textiles and the surrounding corrosion deposits. The various analyses enabled the association of pseudomorphs with extant textiles from the site and aided in the documentation of new textile evidence.