Asked by: Jodie Appleton, New Zealand
Finely crushed glass is basically a very pure form of sand. Technically, natural sand is made of quartz crystals of silicon dioxide, whereas glass is the non-crystalline, amorphous form of silicon dioxide. But when it is ground down enough, the difference isn’t obvious. Crushed glass is sold as an alternative to sand for pool filters – in fact, recycled crushed glass has been considered as a partial replacement for the sand on some of Florida’s eroding beaches.