Sodalite is a well renowned blue tectosilicate lapidary material! It gets its name due to its high sodium content. It tends to work into great cabochons, and takes a great polish. It has historically been mistaken for Lapis Lazuli, due to the bright blue contrast both stones can have.
Measurements (inches - longest - approx): 3.7 x 3.4 x .31
The last photo has been taken dry so that you may see any defects. The other photos have been taken wet to simulate a polish.