In the early 1970s, in the university of Rennes, Jacques Lucas and his co-workers were following the routine of solid-state chemists: the synthesis of new crystals with hopefully new physical properties. Marcel Poulain, a PhD student on a grant from the telecom company Alcatel, had spent time “putting” rare earth inside fluoride crystals. Someday in 1972, after he opened the furnace where the mixture had cooked, he found a disordered matter instead of the usual well-ordered crystal, i.e. a glass. He was about to throw this messy sample away when his supervisor pointed out, after a quick bibliography, that fluoride glass had never been listed. Since giving birth to a new substance is praised among chemists, the team dirtily investigated the chemical product and published a decent article. This case of serendipidity left the solid-state chemistry community cold, but got a few theoreticians from Bell Labs excited when they read the empirical result in 1973: they had just predicted that fluoride glasses would provide optical fibres quicker than the ones in silica by Corning. As speed is the Holy Grail of telecoms, AT&T, NTT, and British Telecom rushed and turned upside down the quiet life of Lucas's laboratory by injecting money to convert bench products into materials. From then on, the capricious nature of fluoride glass reshaped the knowledge of its captive chemists: 1°) through characterizations, from X-ray diffraction adequate for crystals to thermal analysis and spectroscopy for glasses; 2°) through the art of syntheses, from the quest of original structures to the endless optimisation of chemical composition to reach the best possible optical “performance”. This expertise shift entailed a community shift towards an international laboratory network which launched in 1982 an “International Symposium on Non-Oxide Glasses” (ISNOG). The superstar fluoride glass had only needed a decade to shape a new hybrid identity at the conjunction of telecoms, optics, chemistry and materials science. Another decade however was needed for the optimisation on a ZBLAN composition that was sold by a spin-off in Rennes, Le Verre Fluoré. As ZBLAN remained a brand product for high-tech instrumentation and did not reach the mass market, Lucas did not drop his academic identity for the spin-off and went back to the bench to study, with another PhD student, X. Zhang, a new glass based on tellurium. But this time, he got the ISNOG expertise to develop from bench to brand and back.