Wissmach Crystal/ Deep Sky Blue with Luminescent coating (base color code 96-22, a blend Wissmach lists as Peacock Feather Tr/Crystal) is COE 96 kiln glass, a smoky blue Prisma sheet in 3mm with an iridescent surface, tested for fusing compatibility.
Appearance Soft clouds of grey blue drift across the sheet with a brighter sky blue band breaking through, misty and atmospheric rather than sharply streaked, and the coating adds a quiet pearl sheen over the whole surface that shows in ordinary room light. As a Prisma blend the pattern is unique to each sheet, so no two are identical.
Striking Wissmach notes its Opaque and Prisma colors may strike to a deeper or denser color after firing, so the blues here can come back a touch richer than the raw sheet. A sample chip fired first removes the guesswork.
Luminescent coating The Luminescent coating lays a mother of pearl shimmer over the smoky blue base, drifting through silver, lavender and aqua as the light and viewing angle change. The coating is a low fire surface layer and it is heat sensitive. Fired face up, heat and oxygen can burn it away. Wissmach recommends reverse fusing with the coated face down on a flat kiln shelf and keeping the top temperature at 1400 F or below. Do not cap the coated surface with clear glass, capping makes the coating disappear. Keep any later firings below 1250 F. For a full fuse with two 3mm layers, Wissmach’s Luminescent schedule runs 400 degrees F per hour to 1225 F with a 30 minute hold, then 600 per hour to 1400 F with a 10 minute hold, cooling as fast as the kiln allows to 960 F for a 1 hour hold, then 100 degrees F per hour down to 700 F. Results vary sheet to sheet, so test fire a small piece first.
Reactions The base blend is copper bearing on Wissmach's COE 96 chart. Fired against sulfur bearing colors such as String of Pearls, Gold Tone, Honey or the red and orange family, it can develop a darker line where the glasses meet. Run a small test tile before committing a project.
Format and sizes Sold as a 3mm sheet in 8" x 10.5", 10.5" x 16" and 16" x 21" sizes. Choose your size from the options on this page.
Fusing and compatibility Tested compatible with other Wissmach COE 96 kiln glass. With glass from other makers, a matching COE number alone does not guarantee compatibility, so fire a test tile before committing a project.
More of this color Also available without the coating (plain sheet) .
Helpful downloads Wissmach COE 96 Kiln Glass Catalog
Technical data courtesy of the Paul Wissmach Glass Co.
Description updated: August 13, 2026
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