the glass is made up of five layers - two layers of non toughened glass, two layers of resin  laminate, and one layer of toughened glass in the centre. Once the panels have been constructed, a layer of resin is poured, and left to cure for five days, and then the process repeated with the second layer and then they are machine finished; it's during this process that the toughened panel shatters giving the Cracked Ice effect, and because the glass is captured by the resin no fragments can escape leaving a smooth edge.