“In spite of our ability to explain the natural world, there is still a certain mystery to how matter changes form, seeming at first to be one thing, then becoming another. Light things become dark, soft things become hard, solid things begin to flow. Such transformations open onto questions of our own being and becoming and how we find ourselves in a world of flux. Seeing simple mysteries of matter in the elements of earth, water, and fire, may remind us that the universe is an amazing place, a source of wonder. “
All common traditional ceramic base glazes are made from only a dozen elements (plus oxygen). Materials decompose when glazes melt, sourcing these elements in oxide form. The kiln builds the glaze from these, Assuming that all materials do melt or dissolve completely into the melt to release those oxides. Each of these oxides contribute specific properties to the glass. Glazes are sometimes unpredictable.
-I believe there is no bad glaze there are only undesired glazes.
Crystal field theory has long been studied and used to explain gemstone color specifically to characterize how rubies and emeralds both have chromium impurities, but are so contrasting in appearance. Therein, glazes work effectively the same way as gemstones.