K₁₂O₂Se₁₂Si₄

Architectural potential

This is a load-bearing transparent glass tuned for situations where structure and daylight want to arrive in the same element. Five hundred megapascals of compression at 85×85×50 mm puts it into the territory of pressed-glass stair treads, floor panels walked on from above, transparent partitions separating gallery rooms, and light-wells glazed as solids rather than as assemblies of sheet and frame. The selenium-loaded potassium silicate body keeps it inside the soda-lime family in its structural bones, so annealing logic, edge-grinding and transparent-joint detailing stay close to conventional practice — a studio already comfortable with pressed-glass can specify it without a new tectonic vocabulary. Against float glass the embodied CO₂ is effectively flat (roughly two per cent lower) but the firing energy drops by sixty-two per cent, so the environmental argument is a thermal one: the same glass without the furnace day. Natural placements are transparent floor inserts in exhibition spaces, light-admitting treads in public stairs, and pressed-glass beams over reading tables in libraries where the reader looks up into a luminous soffit. The caveat is selenium: elemental Se in the melt demands vapour-handling discipline, and workshop fabrication above 1150 °C should be treated as a chemistry procedure rather than a ceramic one.

Material character

The 50 mm slab reads as a deep clear pool with a very faint selenium-pink blush caught at the long edges — the signature of a Se-loaded silicate melt rather than a coloured dopant. Through the 85 mm face the view sits fully transparent; sighted along the edge it thickens into amber-rose. At 2.79 g/cm³ and this thickness the slab resists a single-handed lift — a deliberate two-hand piece, heavier than a matched float sheet of the same footprint. The top face carries the typical pressed-glass crown with two faint anneal striae running parallel to a long edge. Cold-cut edges show lapidary bloom and a crisp conchoidal kerf — distinct from the blunter edge of the lanthanum-variant sibling.