Their crystallinity is very high and their polytype is 2M_1.Both of them are dioctahedral because the d_(060) and b of micro-crystal muscovite and phengite are 0.1502 nm,0.9012 nm and 0.1505 nm,0.9030 nm,respectively.

• 二者都属二八面体型白云母类矿物；但d060和b值偏大；微晶白云母的d060=0.；1502 nm；b=0