Why is this lump of rock so special?
Ever heard of "Purple Sand" Clay Zi sha
Or seen a Yi Xing Teapot?
purple sand zi sha in mineral form
This raw mineral gets processed into a clay of unique qualities and plasticity that can be hand built slabbed moulde dand thron into objects usually left unglazed because the clay dries and bakes into a glorious red color easily finished without glaze or slip.
So far it has only been found in China though there are similar clays almost as good.
If you ever come across mud or clay or stone that has a similar color reddish purple contact your local potter or geologist!