
Can you turn glass back into sand?
A calm walk along the beach doesn't sound as pleasant with glass underfoot!
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.
Read more:
- Can plastic bottles be reused in the way glass bottles were in the past?
- Why does glass shatter so violently?
Subscribe to BBC Focus magazine for fascinating new Q&As every month and follow @sciencefocusQA on Twitter for your daily dose of fun science facts.
Authors

Luis trained as a zoologist, but now works as a science and technology educator. In his spare time he builds 3D-printed robots, in the hope that he will be spared when the revolution inevitably comes.
Sponsored Deals

Spring Savings!
- Try your first 6 issues for just £9.99 when you subscribe to BBC Science Focus Magazine.
- Risk - free offer! Cancel at any time when you subscribe via Direct Debit.
- FREE UK delivery.
- Stay up to date with the latest developments in the worlds of science and technology.