Good lord that's a labor-intensive process.
I understand that the quality of the final product is important and noticeable by really discerning artists and art lovers, but I'm amazed that anybody still uses this method to produce ultramarine blue from lapis lazuli. I'm kind of glad to know that he uses a different - supposedly secret, faster, and higher-yielding than the Cennini method.
I'll warn you that the later half of the video is mostly about the politics and economics of the mining in Taliban-controlled Afghanistan. It's interesting, but it's not so much about the material production but more about material sourcing.

