Ectobar glass is a highly-strong-but-not-completely-indestructible type of glass. Ectobar glass is shatterproof as well as soundproof. One of the few ways of breaking ectobar glass is with a large and powerful expulsion of energy, like an explosion.
Basileus's Machine is almost entirely made out of ectobar glass inscribed with barrier spells to prevent the imprisoned ghosts needed to power the machine from escaping. It is unknown whether ectobar glass is normal, or is of supernatural nature.