The beautiful beads applied to this adjustable ring are Tila beads, which are square glass seed beads. The color is called coral seas, and has a fun, swirl appearance with coral, brown, and blue.
The mosaic tile square is 20mm, or approx. 3/4 inch by 3/4 inch. The last picture shows an example next to a quarter to help gauge size.
The antiqued bronze brass ring is thin, and also adjustable to fit most adult sizes.