I'm gonna walk through that door.

It applies to "expensive" or high quality glass as well. In fact high quality "crystal glass" is supposed to be the easiest to break with your voice. The only thing that matters is that it's real glass, aka has a crystalline structure and not some kind of polymer.

The freq/harm is able to find a frequency that can break that glass because of any damage/flaws in the glass. Even if the crystalline structure of the glass was perfect when first manufactured... any scratches, abrasions, and microfractures the glass ends up with over time will create fracture points. This is why if you are having issues breaking a wine glass with your voice, try scoring the glass slightly to make it easier. Btw, you don't need to be an opera singer to break a wine glass with your voice, you just need some practice. For an explanation there is this write up and this pbs digital video.

Taking advantage of how any damage to the surface of glass is also how you cleanly cut glass. It works for regular untempered glass (example), laminated glass (example), and expensive borosilicate glass (example). Just remember that tempered glass cannot be cut unless it is first heated to untemper it but then it needs retempered which requires a furnace.

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