Ender Portal Frame

A Crystal Block (unconfirmed name)was added to 1.9 Prerelease 3. It has a luminance of 15 and can be placed underwater just like Glowstone (Block).

The blocks cannot be mined, in those terms they are just like bedrock. However if TNT is used it can destroy them to be picked up.

Crystal blocks cannot be set on fire, nor can be torches be placed on them. Regular blocks can be placed. (needs more testing)