A Buddhist temple in Nanjing, China may have been harboring a major cultural artifact after archaeologists found what they say could be a skull fragment from Siddhartha Gautama, the Buddha himself.

Researchers say the parietal bone was kept inside a model of a Buddhist shrine known as a stupa. The 1,000-year-old meditation piece was discovered in a stone chest, in a crypt underneath the Buddhist temple. Inscriptions found with the stupa claim that the skull bone is from the Buddha himself.

The model is a priceless artifact itself, as it is constructed from gold, silver and sandalwood. Gemstones of varying types, such as lapis lazuli, agate, glass and crystal adorn the outside, and the stone chest the stupa was found in dates the object to 997-1022 CE, during the reign of Emperor Zhenzong of the Song Dynasty. The chest also bears the names of those who constructed the stupa and who financed its construction by donating material and money.