Samian Earth
Samian Earth
Simplified geological map of Samos showing Platanos and the surrounding volcanic rocks that host bentonite and borate deposits—potential minerals in Samian earth(s).
It is well known since the times of Theophrastus, in the fourth century BC, that Samian earth had two main uses; Pliny, in the first century AD, stated that one type was "colyrium", an eye salve, and the other "aster" used on cloth. Theophrastus c.315-305 BC (62-4) describes the material in some detail and gives the methods of its extraction. It was used almost exclusively as fuller’s earth. Galen, Pliny and Hesychius confirm its medicinal and other uses.
As in the case of Lemnian earth, despite historical documentation, Samian earth is distinctly elusive in the archaeological record. Again, the reason is that the raw material, the product itself, the ‘industrial’ waste as well as the workings are readily assimilated into the background of the natural environment.
Guided by geology, IGME's established knowledge on mineral deposits and local knowledge of old clay workings, localities with potential for both borates (a potential antiseptic in antiquity) and fuller's earth (also known as bentonite or montmorillonite, an absorbent clay used as a soap/detergent in antiquity) were sampled for analysis and antiseptic testing, mainly from near Platanos. Although the antiseptic testing was negative the colyrium could well be,or contain, a borate while, as generally assumed in the more recent literature, the aster was probably a type of fuller's earth, an absorbent clay.
Topography near Platanos in western Samos. There are bentonite and borate deposits associated with the volcanic and sedimentary rocks in this area. Thick vegetation means that it will not be easy to locate sites where minerals may have been worked in antiquity.
Scanning Electron Microscope image of bentonite clay from near Platanos.
(SEM secondary electron image) Scale bar 10 microns.
Reference
Chiotis, S, Demou, E., Hall, A.J., Perdikatsis, V. and Photos-Jones, E. (in prep) Industrial Minerals Exploitation in Antiquity in the Aegean: the case of Samian earth.
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