"Biscuit" [bisque porcelain] means fired twice, the first time at 980°C/1,800°F and then 1400°C/2,550°F which is the highest possible temperature for a ceramic and thus gives porcelain its unique qualities: fineness, whiteness, hardness, translucency and sonority. The first firing, known as the "degourdi" firing, will make the pieces porous and allow the glaze to set. As for the "biscuit" pieces, they are not glazed before the second firing, which allows them to keep their matte appearance as here this Legende vase. It's usually said that bisque porcelain is more fragile, but it's absolutely wrong!!