The Mystical Meanings of Blue Agate: A Closer Look One of the few gemstones that embodies inner beauty is blue agate. Before we begin our discussion on blue agate, let's discuss what agates are. Agates are a variety of chalcedony. From the surface, or from outside, they look distasteful and less desirable. However, when these stones are cracked open, you will discover a beautifully banded and vividly patterned interior.