Maya Blue

Archeologists have figured out how the Mayan people made the so-called "Maya Blue" color associated with sacrifices.
There was more than the obvious reason to feel blue for people offered in human sacrifice rituals by the ancient Maya to their rain god -- they were painted blue before being heaved into a watery sinkhole. And it wasn't just any blue. It was Maya blue -- a vivid, somewhat turquoise-colored pigment used for about a millennium by Mesoamerican peoples to decorate pottery, figurines and murals that has long mystified scientists..... During the rituals conducted on the edge of the cenote at Chichen Itza...the Maya seem to have produced the pigment and painted items like pottery that would be tossed into the water as offerings to the god. (Human sacrifice was part of rituals appealing to the Maya rain god Chaak -- depicted on some Maya structures with a unique elongated, curled nose -- to deliver rain for crops such as corn.) And...they also would paint people being offered as human sacrifices blue and heave them into the sinkhole....(A)bout 120 sets of human remains have been dredged from the sinkhole, along with lots of ceremonial objects.... (A)t the bottom of the cenote, a layer 14 feet deep of blue goo has been found, likely composed of pigment that washed off sacrificial victims and objects.
The pigment was made of indigo, copal incense and palygorskite, and prepared fresh at the edge of the cenote for each sacrifice to Chak.
(screenprint; photo of Chak-nose fountain by me)
12 19.15.2.3 11 Kayab 2 Akbal