Israel

How can you know how long it’s been since a grain of sand last saw sunlight? Shine a light on it!

Quartz grains, the most common sand type, store information about how long it’s been in the dark. With Optically Stimulated Luminescence (OSL), it’s possible to determine exactly how long ago sand was exposed to sunlight or extreme heat.

Analysis of sand grains in Israel’s Qafzeh Cave revealed a big scoop – modern humans were in places like Israel far earlier than thought.

OSL technique on sand helps geologists and archaeologists to date events up to a few hundred thousand years back in time with high accuracy. (If it’s about millions, you need to find zircon sand grains instead, but that’s another story)

As they say, every grain of sand has a story to tell!