Investigation methods for evaluating the preservative organic mixtures applied on a Late Period mummy

The resins and other biochemical substances in mixtures have an important role in achieving the preservation goal for mummification process. The identification of organic mixtures is vital in the conservation field of the unwrapped mummies, but their identification is sometimes difficult because of improper conditions, which can affect their structure and need good investigation techniques for their identification. Some endogenous or exogenous factors can cause some aspects of deterioration to organic mixtures such as cracks, color change, and chemical alteration. This study aims to evaluate the materials used for the preservation of the body in order for them to be re-used in the near future for the preservation processes on the unwrapped mummies in Egyptian museums and storehouses. Samples of organic mixtures were taken from an ancient Egyptian mummy dated to the Late Period (664-333 B.C.). A digital USB microscope and a scanning electron microscope (SEM) were used to identify the application method of the preservative mixtures used during the mummification process and to demonstrate the morphology of surface alteration on the body. Fourier transform infrared (FTIR) was used to detect the chemical changes. A portable X-ray fluorescence (XRF) was used to identify elements. The results revealed that the investigation by microscopes showed cracks in the mixtures poured inside the cranial cavity, but the application of these mixtures was by brush on the outer surface layer of the body. FTIR analysis revealed that a mixture of oil, animal fat, and resinous materials such as mastic and pine were present in the studied samples. Moreover, these samples were prone to oxidation processes through time. XRF analysis showed that the main chemical elements of the samples were calcium, potassium, phosphorus, chlorine, sulfur, and silicon and trace chemical elements such as iron, zinc, copper, and lead, which are in the chemical composition of pine and mastic resins.