What is "hematinon"

Hematinon \He*mat"i*non\, n. [Gr. a"i^ma, a"i`matos, blood.] A red consisting of silica, borax, and soda, fused with oxide of copper and iron, and used in enamels, mosaics, etc.

n. A red colour consisting of silica, borax, and soda, fused with copper oxide and used in enamels, mosaics, etc.