When the Ru kilns fired celadon, the ware was first fired in oxidation flame, then in reduction flame. The temperature was kept at relatively low levels (1125 to 1225 degrees Celsius), followed by a period of natural cool down so as to cause crystallization in the glaze. The rich amounts of crystals covered more than half of the glazed area. Sparse air bubbles also formed. Since Ru celadon experienced good crystallization during the firing process, its glazed surfaces not only showed a sky-blue color, a jade-like turbidity was also present.
This celadon Gaiwan is slight heavier than the ones that were made from porcelain. The gaiwan would absorb a lot heat because of its thick wall, I would strongly advise to warm Gaiwan properly by leaving the hot water inside a bit longer than usual before your first brew.
This Gaiwan is beautifully finished with very smooth surface, just exquisit like beautiful jade. You can see the crackles in the new ones, and the glaze crackles will become darkens after you use it few times and banishes the milky finish.
As the Gaiwan is glazed, it would only darken the glaze crackles but will not absorb any flavour from tea. It is a great piece for any kinds of teas.