As its name implies, fiberglass consists of fine-spun filaments of glass made into a yarn that is then woven into a rigid sheet, or some more pliant textile. Parisian craftsman Dubus-Bonnel was granted a patent for spinning and weaving glass in 1836, and his process was complex and uncomfortable to execute. It involved working in a hot, humid room, so the slender glass threads would not lose their malleability. And the weaving was performed with painstaking care on a jacquard-type fabric loom. So many contemporaries doubted that glass could be woven like cloth that when Dubus-Bonnel submitted his patent application, he included a small square sample of fiberglass.

From: Extraordinary Origins of Everyday things
by: Charles Panati