Wow, it does not look an ancient stuff. I think it's last longer than clay and other if am not mistaken.
Nice pictures, I have seen some in Nigeria too at art and culture department in my school then.
Thanks for sharing this knowledge.

I have a post I would love you to see.
https://steemit.com/steemit/@captain-tom/celebrating-2-weeks-as-a-steemians-secret-and-benefits-of-steemit-i-discover-will-help-other-minnows-grow