I've learned so much in the last day and a half from this site! Have had so many disappointments with glazes that had work well for me in the past, then one by one, 4 of my most trust-worthy glazes began failing me. Waterfall Brown, licorice, Variegated Blue, and another glaze (Straw glaze) not from the MC6G book were all turning my pieces a dark ugly brown instead of the beautiful mottled and textured colors that I had grown to love. I was wracking my brain trying to figure out what was going on. I haven't changed kilns - same firing schedule. Nothing made sense to me. After reading through page after page of comments in this forum, I am now wondering if it has to do with the brand of RIO that I purchased last fall (all the glazes that have failed me contain RIO). I just zipped over to the US Pigment site for the first time ever and ordered some high purity RIO. Fingers crossed!
Update: Just looked up where I purchased my last order of red iron oxide and, lo and behold, I got it from Axner.com. At the bottom of my receipt it says "a division of the Laguna Clay Company". Thank you Norm Stewart for your post!