Originally Posted by
Marshal
Cursory search of Mujingfang leads me to believe it's a tool maker:
"Mujingfang gathered the best plane makers from around the country and brought them to their Hong Kong factory from where they supplied master craftsmen throughout South East Asia. Recently, they decided to offer their handmade planes to Western woodworkers."
Perhaps they bought the mine, or just a large chunk of the stones, and gave them their own in-house name instead of relying on the Guangxi label we're familiar with?