Thank you for answers, Charles!
Recently I have seen a teapot made from some strange material that was named 清宫御用金砂配方 by the seller.
Do you know something about this clay/mix?
I saw some pots with the material listed as that aslo, from what i could find out 清宫御用金砂配方is紫砂泥
清宫御用金砂配方is not pure 紫泥, 紫砂原料or清代的宫廷原料配方结合自己学识独特配制而成.