Friends, don’t adjust your monitor, these clay beds are definitely blue.  This bentonite clay, the raw material for scoria formation, is often found adjacent to stripes of  lignite coal.  Bentonite can be used in pottery to form ceramics and glazes as well as other commercial applications.  The most valuable applications are dependent on the ability of very small particles to hold water .  Suspensions, colloids and emulsifiers made with bentonite are commercially viable.  When water hits these bentonite slopes, the surface is extremely slippery, sticky and mucky.  Many times I have come back to camp with clay snowshoes attached to my boots that take days to wear off.  til Tomorrow MJ