Home Index Site Map Up: Home Navigation
Up: Home
Gustave Falconnier's Blown Glass Bricks
Home  > Falconnier
First: Glass Insulators Last: Glass Feet and Legs Prev: Glass Insulators Next: Overmyer's Threaded Glass Drawer Knobs Navigation
Topics: 2 of 7

Falconnier briques at the house of Mihály Babits, famous Hungarian writer, poet, translator, and literary historian

·Catalog
·Patents
·Gallery
·Articles

Falconnier briques in the Castel Béranger

Falconnier full and half-size bricks

Dora and Marinus Wassenbergh

Cobalt #9 brick from Cole's Book Arcade, via Victoria Museum
Falconnier brique seal
Brique seal
History: In the late 1880s, Architect/Engineer Gustave Falconnier [1845-1913] of Nyon, Switzerland, invented a novel form of glass building block or "glass brick" (German glasbausteine, French brique de verre). Falconnier's bricks were hollow, blown in mold (BIM), and had the original feature of being sealed air-tight with a pastille of molten glass while hot; after cooling, the hot air trapped inside contracts, forming a partial vacuum.
Unsealed hollow glass blocks by Deutsche Luxfer Prismen-Gesellschaft
Unsealed hollow glass blocks by Deutsche Luxfer Prismen-Gesellschaft
Earlier glass bricks such as those by Siemens and Deutsche Luxfer Prismen-Gesellschaft were unsealed and shaped like traditional masonry bricks (but without a bottom surface); they had problems with condensation and dust collection on their interior surfaces. Unsealed hollow glass blocks by Siemens of Dresden
Unsealed hollow glass blocks by Siemens of Dresden

Briques were manufactured by Albert Gerrer of Mulhouse (Haut-Rhin), S. Reich & Co. of Vienna and others. Their sides were recessed to take mortar and they were laid up like ordinary masonry bricks, with or without metal reinforcing embedded in the mortar. Falconnier's hollow, air-tight design, a prize-winner at the 1893 Chicago World's Fair and 1900 Paris Exposition, had several advantages:

"By making such bricks or blocks hollow, especially when they are made air-tight, they possess several advantages over other materials, being cheap, light, durable, and ornamental. Further, by reason of their inclosing and confining air in a state of rest they serve as non-conductors of heat."US Patent No. 402,073

Haywards Ltd. bought the patent and marketed them in England for vault and window walls. Despite initial interest from important period architects such as Hector Guimard, Auguste Perret and Le Corbusier, and some prominent installations (La Mission d'Algérie, house of Mumm, etc), Falconnier's design was apparently not a great commercial success. The bricks are rare today, and existing installations even rarer. They suffered from the same defect as early vault lights: damaged glass could not easily be replaced. Falconnier briques are sometimes mistaken for fishing net floats.

Markings: All Falconnier bricks are marked with embossing, usually "FALCONNIER / DEP FRANCE BELGIQUE + nnn / FRANCE" where nnn is the style number, most commonly 8. Bricks produced at other factories have different markings, but they all proclaim "FALCONNIER".

Partial bricks: For finishing square openings, each brick was also made in ¾, ½ and ¼ sizes. A ¾ brick finished the long side, a ½ brick finished the short side, and a ¼ brick finished a corner. Partial Falconnier bricks

Colors: Most bricks were light aqua, the usual color of glass made from sand with iron contamination (which is most sands, as any child who's played in a sandbox with a magnet can attest), but other colors were available at extra cost: clear for improved light transmission, and decorative colors amber, green, blue and (opal) milkglass (all colored in the mass). A red brick was made by casing a clear brick in a thin layer of expensive, gold-based ruby glass. The patent mentions coloring "either in the mass or by coating or covering them inside or outside in full or in part with layers of metal or paint", Additional ornamentation by sand-blasting, cutting and engraving, or acid etching is also mentioned, but I have yet to see these variations.

Value: Despite rarity, prices are low since there are very few collectors of early glass bricks (basically: me), so there is little demand. The most common brick, the #8 in light aqua, is difficult to sell at any price. I have seen hundreds for sale (often in large lots), and would price them at about US$5. Rarer patterns and colors are worth more, as are partial bricks. The high end is about US$150.

Finis: Modern-style two-part fused glass blocks were perfected in the 1930s, more than forty years after Falconnier's bricks were introduced. Around the same time, Belgian company Etablissements Gaston Blanpain-Massonet of Bruxelles was still producing bricks in the #8 pattern (always the most popular) as seen in this catalog page, as well as the glass bricks of style Glasfabriek Leerdam.

Nyon: See this article on Falconnier by the City of Nyon Archivists for more about his history, and additional photos: La brique de verre Falconnier.


Four basic shapes were produced: square (No. 6, in two variations), a lozenge or watch-with-band shape (No. 8), squashed hexagon (No. 9), and four variations of a regular hexagon (Nos. 7, 7½, 10 and 11). All tessellate, forming a repeating pattern that completely fills a space. No. 8 was the most popular shape and so is the most common now, followed by No. 9 (also fairly common), then regular hexagon and square, which are rare; ratio is about 250:50:5:1.
Falconnier block glass brick No. 6 (front view) Falconnier block glass brick No. 6 (side view) Falconnier block glass brick No. 7 Falconnier block glass brick No. 8 (front view) Falconnier block glass brick No. 8 (side view) Falconnier block glass brick No. 9 (front view) Falconnier block glass brick No. 9 (side view)
No. 6 No. 7 No. 8 No. 9