Terracotta

I found the following statement on an other discussion group.

   "Old terracotta's have manganese metallic traces that are easily
    recognisable by visual inspection, they look like lichens and
    can be used to authenticate."

Has anyone researched this, is there a paper or article about this?

Dr. Robert B. Faltermeier
Faltermeier
Conservation - Restoration
8B Keong Saik Road
Singapore 089116
+65 6323 1360
Fax: +65 6323 7642


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                  Conservation DistList Instance 20:30
                 Distributed: Friday, December 1, 2006
                       Message Id: cdl-20-30-013
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