Mineralogical characteristics, of Li-bearing tosudite from the Bubsoo
mine, Korea was studied using X-ray diffraction analysis, chemical ana
lysis and electron microscopy. Tosudite occurs as cryptocrystalline fl
aky aggregates in the alteration zone of Cretaceous Juwangsan volcanoc
lastic rocks in the Bubsoo mine. It coexists with microcrystalline qua
rtz, dickite and interstratified mica/smectite in the inner alteration
zone. XRD and chemical analyses suggest that the tosudite is an 1:1 r
egular interstratification of Li-bearing donbassite and beidellite. It
contains 0.44 wt.% of Li2O. Potassium is the main interlayer cation.
The Li-bearing tosudite might have been formed from the hydrothermal s
olution having high activities of Si and Li, but low activity of K und
er relatively high temperature.