Hair knives
Tuareg peoples, northwest Africa
93-6-8, gift of Mrs. Florence Selden

A Tuareg artist skillfully constructed each knife handle by laminating and shaping metal and other black, brown, and white materials. At first, it was assumed that the non-metallic laminants were made of readily available natural materials--perhaps wood, shell, and coconut shell. However, a researcher in the field had speculated that the laminants were linoleum.

To identify the material, Fourier transform infrared (FTIR) spectroscopy was performed on a sample of the laminant. The strong, broad absorption bands from the 1000 cm-1 to the 1100 cm-1 region in the FTIR spectrum indicates that the material is a urea formaldehyde plastic. Developed in 1928, this material has been used to produce such domestic items as dinnerware, bathroom panelling, and kitchen table tops. This plastic is sometimes generically called linoleum.

This analysis helped to establish the earliest possible date of manufacture for the knives and to identify the increasingly diverse trade network that enabled Tuareg craftsmen to use new materials in traditional ways. Equally important, it influenced storage decisions. The initial proposal to store each knife in a polyethylene bag to retard tarnishing proved to be inappropriate. Because urea formaldehyde produces formaldehyde and ammonia as it degrades, the individual bags would contain an unsuitable microclimate. Instead, non-airtight storage containers were lined with sulfur scavengering cloth.

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