Physical-Chemical characterization of Sea-silk and its crafting phases

The sedentary mollusc Pinna nobilis L. produces fine but strong filaments of fibre beard called “byssus”. This fibre has the task of fixing itself to the sea grass and withstand the flow. Byssus was the basic raw material used to make Sea-silk, but this Mediterranean species is protected since 1992 [1] and production of its iridescent golden textile is therefore impossible. In the history of textile, Sea-silk constitutes a very small part, it is proven that the use of Sea-silk dates back to at least the Roman age while, today, Sardinia and Apulia (Taranto), are the production centres of Sea-silk and keep their importance. We studied samples of sea-silk kept at Commodity Science Museum of Bari University, where one valve, some pearls and all the different phases of crafting of this textile are represented, starting from the raw byssal threads up to the woven textile. The aim of this research is to characterize the threads from a morphological and chemical point of view considering above all the evolution and changing of the material with the different working phases. Due to the samples uniqueness, the smallest amount possible is taken from the byssal threads (about 20 mg). We used different techniques like optical microscopy (OM) and Scanning Electron Microscopy coupled with Energy Dispersive Spectroscopy (SEM-EDS) aimed to the observation of the morphological changing of the fibers examined in their different handmade production steps and ICP-MS for the determination of metal composition in some fibers after their mineralization and in deionized water, observing the metal lost characteristic of the desalination process. The results obtained show how the metal concentrations analysed, decrease after the different crafting steps, and the fiber of the Sea-silk change its microscopic aspect until to obtain the golden “soul of the sea”. [1] http://www.muschelseide.ch/it/biologie/byssus/faseranalyse.htm