Feldspar an overview | ScienceDirect Topics
A typical dental porcelain will mainly consist of a mixture of feldspar with, say, about 15 ~ 20% powdered quartz and a few percent of kaolin as a binder. Kaolin is an hydrated clay mineral, Al 2 O 3 ·2SiO 2 ·2H 2 O, and is in the form of very fine hexagonal plates in the range 1 ~ 5 μm diameter and about 1 μm thick.