In the top photo there is a spoon of jade wetted with reddish cinnabar remains in the cuts. The cinnabar pigment was of great value and sacred to the teachers and used to decorate objects and walls. But the cinnabar is an 85 percent mercury mineral, and therefore very toxic.

Currently, archaeologists have found dangerous levels of mercury in some layers of the deposits and, as reported in the journal Frontiers of Environmental Science, are convinced that this affected Mayan health. But it remains to be seen whether it was one of the main factors in the sociocultural changes at the end of the Classical Era or not.