This 19cm magnetic hourglass is filled with green iron filings.

When placed on its circular magnetic base, the metal grains will start to fall, creating mesmerising and beautifully spiked sculptures in the lower chamber.

This hourglass is not intended as a real time-keeping device, and even though the timer goes for approximately for two minutes, the actual time may vary.

If the sand stops filtering through then it has become magnetised, and you simply need to shake the hourglass for it to start flowing again.