Chun glaze by itself is actually transperent and close kin to celadons however put some blue slip under it add a wash or splash of copper oxide and you can get wonderful colors ranging from red to purple.
This is actually slightly odd since copper fires green or red by its self.
Somehow the glaze and the oxides alter in synergy during firing.
The Japanese have a wrod for it. YOHEN Kiln Change.
A neighbour down the road has a rose bush that flowers for a few days before the lilac - mid purple roses get stolen or she maybe cuts them off before they can get stolen. It has just two or three exquisite roses