Amazonite is a blue green Feldspar (same family as Moonstone) Generally opaque or slightly translucent, the best qualities have a nice consistent colour but generally there are white inclusions. Popular for carvings & amulets in Ancient Egypt, it's now regaining popularity in Jewellery.
Perhaps because it's an excellent emotional healer and helps smooth aggression like the proverbial oil on troubled water. It opens the Heart and Throat chakras, again aiding emotional expression. If you're facing an emotionally tense situation and want to stay cool and centred, this is an excellent stone.