The stars in Orion's belt are actually all white stars, but they can appear to have slightly different hues depending on factors like:

* Atmospheric conditions: Our atmosphere can scatter blue light, making stars appear redder.

* Our perception: Our eyes aren't perfect color detectors, and the brain can interpret colors differently.

However, the three stars in Orion's belt, Alnitak, Alnilam, and Mintaka, are all classified as blue-white supergiants. They emit a lot of blue light, but because of their distance and the factors above, they often appear white or slightly yellowish to our eyes.