Is glass a bad omen?
The glass armonica quickly became a bad omen for any who listened or played it, due to what happened to the listeners at the time. The Armonica was accused of causing evils such as nervous disorders, domestic squabbles, premature deliveries, fatal disorders and convulsions in animals. After the death of a child, while listening to this instrument, the glass armonica was banned in a german town. When this happened, glass instruments quickly became a bad omen, with tales of them rising the dead them scaring animals, causing premature births and raising the spirits of the dead. These superstitions meant the instrument was illegal to be played after midnight and near a graveyard.
Looking at glass in general as a superstition nowadays, accidentally breaking glass supposedly brings good luck, and coming across glass is a warning that a relationship will end. But apart from that, modern-day views of glass instruments have completely changed and barely anyone is scared of them, due to their obscurity.
Barely anybody knows about glass instruments, let alone the glass armonica. Because of this, the history of glass instruments is only known by a few who are extremely interested in this odd family of instruments. Because of this, the bad omen of glass bowls in the 18th century was forgotten and in the modern-day, glass has little superstition towards this topic.
Sources
http://johnroach.net/the-evils-of-the-glass-armonica/