Due to its favorable geographical location and the significance of the sea in ancient times, Tipasa had several mooring sites along its beaches, bays, and islands. Not far from the beach at the commonly called Sainte Salsa, archaeologists discovered two fragments belonging to the neck of a terracotta amphora of Dressel 1C type, likely used for transporting wine. In this study, it is characterized the terracotta used in the amphora through various investigative techniques: morphology observation under a binocular microscope, petrographic analysis on thin sections, mineralogical analysis using X-ray diffraction, and petrographic analysis (porosity, water absorption, density, etc.). The results indicate that this terracotta was made from clay mixed with tempering agents (sand and straw) to reduce paste plasticity. It was fired in an oxidizing atmosphere at low temperature, as evidenced by the presence of calcite in the shard (incomplete degassing), resulting in high porosity and water absorption. For the restoration of these two fragments, we performed mechanical cleaning of concretions, yielding satisfactory results, followed by a "peeling" mechanical treatment using Klucel®. Subsequently, a complementary chemical treatment was applied to remove remaining CaCO3 carbonates with citric acid and EDTA. While the chemical treatment successfully eliminated dirt and white stains, some areas persisted as white film-like stains. Elemental chemical analysis using SEM-EDS indicated that these areas were primarily composed of silica (SiO2), suggesting diatoms, organisms with siliceous skeletons challenging to remove with chemical treatment. The use of strong acids was avoided to prevent damage to the calcareous and porous terracotta. Thus, the cleaning process was halted, and the restoration process continued (reassembling, bonding with Paraloid72 at 30%, filling with molding plaster using the balloon method, and finally coloring).
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Dec 31, 2024
Yu-Ri Na 
Open Access