Under Construction August 2011
Most ceramics we see in Alaska have a porous structure that can allow water soluble salts from the ground or from seawater to penetrate. When the water dries, these salts can crystallize on the surface. If the item is glazed, the salts can cause the glaze to pop off the surface in small spalls because the glaze is made of glass and is not porous. Alaska Native cultures have few traditional ceramic technologies, with the major exception of a coarse, heavily tempered ceramic. Historical ceramics from the Russian period, through the gold rush and homesteading periods up to modern times are seen in Alaskan collections.
2. POSSIBLE CAUSES
The most common white stuff we have seen on Alaskan ceramics tends to be salts from burial or contact with seawater. Adhesive residues are also common and are usually associated with the break edges. Adhesive residues from labels have also been seen. At the Alaska State Museum, we attempted to force salt crystal growth on ceramics. We gathered high-fired ceramic china from the beach site of the old Treadwell Mine dining hall on Douglas Island, but could not get any crystals to appear on that ceramic. At the same site, which is subjected to tidal action, we also buried a smashed contemporary terra cotta flowerpot for several days. That pottery readily yielded nice crystal salt growth after only a short time in the lab oven.
Harry, K.G. and L. Frink. (2009) “The Arctic Cooking Pot: Why Was it Adopted?” American Anthropologist 111(3):330-343.
Harry, K.G., L. Frink, B. O’Toole, and A. Charest. (2009) “How to Make an Unfired Clay Cooking Pot: Understanding the Technological Choices Made by Arctic Potters. Journal of Archaeological Method and Theory 16 pp.33-50.
Frink, L. and K. Harry. (2008) “The Beauty of “Ugly” Eskimo Cook Pots.” American Antiquity 73(1):103-120.
Paterakis, A.B. (1987) “The Deterioration of Ceramics by Soluble Salts and Methods for Monitoring their Removal.” In Recent Advances in the Conservation and Analysis of Artifacts. Institute of Archaeology, Jubilee Conservation conference pp67-72.
Pearson, C. (1987) “Deterioration of Ceramic, Glass and Stone” Conservation of Marine Archaeological Objects. Butterworths. London.
4. EXAMPLES IN ALASKA