Wissmach Crystal/Black with Luminescent coating (base color code 96-25) is a Prisma blend in COE 96 kiln glass, swirled crystal and black in a 3mm sheet with an iridescent surface, tested for fusing compatibility.
Appearance The coating turns the swirled sheet into a wash of mother of pearl color, with lavender, green, gold and teal drifting across the surface as the angle changes, and the effect shows in ordinary room light, no special lighting needed. Underneath, Prisma puts two colors in one sheet with the first in the name dominant, so clear crystal carries the sheet with smoky black tracing through it. The swirl is unique to each sheet, so no two are identical.
Striking Like Wissmach's other Prisma sheets, this blend may strike to a deeper or denser tone after firing, so expect the fired result a little richer than the sheet looks unfired. Test a sample chip if the exact shade matters.
Luminescent coating The Luminescent coating lays a mother of pearl shimmer over the swirled crystal and black base, drifting through lavender, green, gold and teal 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 not flagged on Wissmach's COE 96 reactive chart. It sits next to any color in the line without forming a reaction line, so you can place it anywhere in a layout without planning around chemistry.
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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