Zhaocun bentonite deposit oringnated from tuff rich in volcanic hyalocrystalline,which underwent hydrolysis and alteration in Changxing county,Zhejiang province.The deposit has middle scale.
Research shows that the dawsonite in Hailaer Basin exists in both the eroded volcano tuff and sedimentary volcano tuff,and is paragenous with corrensite and allevardite frequently.
The word " tough" can also mean simply very difficult – something that causes you problems. You may say see someone spell " tough" (tuff), though to be honest I've never actually seen anyone spell it that way.