2mm (Thin) Bullseye Opalescent Sheet Glass - Steel Blue.
This is a remarkable colour which stays blue when fired under a transparent glass or when overglazed, providing it is covered when fired. It also forms a pewter metallic film at lower temperatures if left uncovered. See the 'Special Effects - Steel Blue Opal' tipsheet, and start experimenting!
May react with:
At tack fusing temperatures, the surface frequently develops a metallic gray film. This usually disappears at full fusing temperatures. To avoid metallic filming, use an overglaze or cover with thin clear glass. To maintain the metallic effect, fire as quickly and low as possible. Consider stencil spraying of an overglaze to create patterns of metallic and non-metallic blue. Dark interface reaction likely with sulfur glasses (001137, 001437, 000137).