MAC Atlantic Blue Eyeshadow ($17.00 for 0.05 oz.) is a medium-dark, cobalt blue with a matte finish. It has decent, fairly buildable pigmentation, but it can be hard to blend out as it is a little drier and thinner. It is somewhat more manageable over a primer, but I have the best luck using it primer and then layering it on top of another eyeshadow for added depth. The color wore well for eight hours on me.
FURTHER READING: Formula Overview, which is a detailed review of the range as a whole.