Can geologists guess where you've been on holiday from the sand in your backpack?

Does it fascinate you that sand from different places looks and feels different? The answer lies in its mineral composition and its journey through time.

Assistant Professor Arjan Dijkstra knows all about it. In fact, rumors say he can tell where sand comes from—without ever seeing it. That’s exactly what we’re putting to the test!

To do that, we’re using the X-ray Diffraction (XRD) scanner, a machine that uncovers the hidden mineral makeup of sand by generating a unique pattern of peaks on a graph called a diffractogram. Geologists then compare these patterns to extensive online mineral databases containing thousands of minerals to identify what’s inside.

But here’s the real challenge: Can Arjan do the same without a computer?

And even more impressively, can he tell us where the sand is from just by analysing a diffractogram?

That's what this series is dedicated to. We’ve gathered sand that somehow made its way home with us after our holidays (oops!), and we’ll see if Arjan can trace it back to its original beaches.

In this first episode, Arjan walks us through how the XRD works and what those strange graphs (diffractograms) mean.

Next up: We put Arjan to the test with his first diffractogram!