Stars can appear in a variety of colors due to their temperature and size, with blue and purple hues typically seen in hotter stars. However, stars that appear distinctly purple and blue are relatively rare.
Stars in the blue region of the spectrum are usually O-type or B-type stars, which are very hot, massive, and have short lifespans. These stars can emit light that appears blue or bluish-white. Stars that might appear purple could be the result of various factors, including atmospheric scattering effects, the presence of certain elements in the star's atmosphere, or even the observer's location and viewing conditions.
In astronomical terms, while blue and possibly purple stars (through selective coloration effects) can be found, they are not the most common. Most stars in the universe are yellow (like our Sun), orange, or red. Therefore, the occurrence of stars that distinctly appear purple and blue is indeed rare.