The icicles are made from hollow tubes of borosilicate glass, which is made for science to withstand shock, stress, pressure, extremes of temperature, gas, acid, and 1st year chemistry students. After forming them in the fire, each icicle is then annealed, that is put in a kiln, brought up to temperature, held at that temperature, and brought down to room temperature. This eliminates the stress from the glass. The icicles are then capable of being used as a musical instrument. My icicles are not unbreakable, but they are shockingly tough. Not your grandmother's icicles at all, but definitely inspired by them. I make each one myself in my studio in Aberdeenshire, Scotland.
Each one is hand made and so they are all a bit different as you can see from the photos.