I believe the Chinese used fairly conventional mineral oxides, such as any glassworks would use. Cobalt for dark blue, manganese for pink, etc. I believe their red glass was most likely imported, as was the avventurina (at least initially).

A story circulates that the Chinese colored their glass with ground up precious stones. (Similar things are sometimes said about Persian/Afghan enamels). This is not true at all, of course.

Jamey