What is this picture?

Question

What is shown in this image?

Accepted Answer

used match head (macro). The colorful coating on a used match head is actually a brittle glass-like substance created by the intense heat of combustion, and under a microscope it reveals a chaotic landscape of tiny crystalline structures that look completely different from the smooth, uniform coating on an unburned match. This transformation happens so fast—in just a fraction of a second—that it essentially freezes the chemistry of burning in place, creating a tiny snapshot of a chemical reaction in progress.

Answer: used match head (macro)