Pure Celestine is colorless, but impurities give this mineral a wide range of colors. The most common color is light blue, which is often  caused by irradiation of gold.

This light blue tint may be present in a whole specimen, or may only be confined to one area. Celestine is isomorphous with Barite, and may partially replace it.

Celestine is the most common mineral containing the element strontium, and is its primary ore. It is a popular mineral among collectors.