Pleochroic halo

Pleochroic halos are special types of circles or rings that show up around certain kinds of rocks when you shine a light through them. Some of the rocks have tiny, round crystals inside them and when the light passes through these crystals, it makes special colorful rings which look like halos, or circles of light. The colors of the halos and the brightness of the halos can tell a scientist a lot about what kinds of minerals are inside the rocks!