What is this picture?

Question

What is shown in this image?

Accepted Answer

chalk dust particles. Chalk Dust Fun Fact When you write on a chalkboard, you're actually creating a tiny explosion of calcium carbonate particles so fine they can stay suspended in the air for hours—which is why chalk dust has been linked to respiratory issues in teachers and why some schools have switched to whiteboards. What's wild is that the same calcium carbonate in chalk is also the main ingredient in antacids and eggshells, meaning classroom dust and stomach relief are chemically identical!

Answer: chalk dust particles