What are Micros? Micro's are short for microcrystalline which is a glaze that develops small crystallization from the the zinc and silica during the cooling process. Micros do not actually contain a glass crystal like our other stoneware crystal glazes, Rather, the effect is created by the glaze itself during the firing process. These glazes can be fired from cones 5-10, but the crystallization may not form at higher temperatures. The micros are not dinnerware safe due to surface durability. We recommend using micros on the outside of dinnerware, below the lip line or on decorative wares.