Cattle bone powder first discovered in pottery bonding from China's ancient horse statue

BEIJING, May 20 (Xinhua) -- Chinese researchers have discovered cattle bone powder for the first time in an ancient adhesive of a pottery horse excavated from a tomb that can be traced back to the Han Dynasty (202 B.C.-220 A.D.) in east China.

The findings have been published on the Journal of Cultural Heritage in its May-June volume recently, which provides a reference for the study of ancient adhesives and a scientific basis for the production of ancient pottery, according to the researchers from the School of Cultural Heritage of Northwest University and the Qingzhou Museum of Shandong Province, east China.

Archaeologists salvaged a funerary pit close to the tomb in Qingzhou in 2006 and discovered more than 2,000 painted pottery figurines made of grey clay, one of which, a horse, looked to be repaired using an adhesive substance.

Adhesive samples from fragments were taken in and researchers examined the samples by multiple techniques, including optical microscopic observation, scanning electron microscope-energy dispersive spectroscopy, X-ray diffraction and infrared spectroscopy. The findings indicate the presence of burned bone powder and clay in the samples.

Proteome revealed that the origin of the animal bones in the adhesive is bovine. Based on replicated experiments, it is believed that burnt bone powder was produced by being fired at about 250 Celsius degrees after being grinded, according to the study.

The ancient adhesives are closely related to pottery's assembly and repair processes, demonstrating the technical levels at that time.

Organic substances are found widely used as adhesives by ancient Chinese craftsmen. For instance, pitch and tar have been applied to repair broken containers or to fix decorations. Lipids, animal glue (liquid glue prepared from animal skin and bones), plant gums and bee wax have all been used to bind things together.