Glass prisms have been used since the 1800’s to transmit light through cast iron panels and by the turn of the century the New York City subway system had used vault lights extensively to illuminate underground subway stations with natural light. Richmond Iron has designed glass prisms using industrial quality glass molding to replicate historic glass for restoration or new installations. A lighted vault panel, stair tread or riser really starts with the glass and Richmond Iron offers a wide range of design options.
Glass Prism Options
Richmond Iron has three different glass prism designs for cast iron stair treads, risers and panels. These prisms are molded by Gillinder Glass with dies designed by Richmond Iron for a perfect integration of glass and cast iron.

2" dia. Pebbled Top Prism Glass
2 inch dia. prism glass with domed pebbled top. The pebbled surface adds scatters backlighting and adds brilliance.

2" dia. Flat Top Prism Glass
2 inch dia. prism glass with flat smooth top. Flat top glass installed flush for a walkable surface.

1.75" dia. Flat Top Prism Glass
1.75 inch dia. prism glass with smooth top. Flat top glass installed flush for a walkable surface.
Historic Examples of Glass Prisms in Cast Iron
Projects with Glass Prism Cast Iron from Richmond Iron

70 Greene Street, Cast Iron Vault Lights, NYC
Custom cast iron vault panel castings and glass prisms for 70 Greene Street.

36 Hudson, NYC, Cast Iron Vault Lights
Cast iron vault lights, 36 Hudson, New York City.

REI SOHO, 303 Lafayette, Manhattan – Cast Iron Stair Treads, Risers and Panels
Custom cast iron stair treads, cast iron risers and cast iron landings for REI SOHO, 303 Lafayette St., NYC.

Bancroft & Co., North Shore Mall, Boston, Cast Iron Staircase
Complete custom cast system of cast iron stair treads, cast iron risers and cast iron landing panels for the Bancroft & Co. restaurant, North Shore Mall, Boston.

401 Park – The Fenway, Boston, Cast Iron Staircase
Cast iron stair treads and risers with prism glass custom cast and finished for 401 Park Building, Boston.