Elemental - A very useful multifaceted periodic table of the elements.
Version: 0.1 Alpha 1Elemental is a multifaceted periodic table of the elements with search capabilities. It is currently still largely under development, but I have deemed it stable enough for a an alpha release.
Operating System: Mac OS X
It features colourful tables and legends, an information window with masses, and tables not only of the traditional type, but of crystal structures, electron blocks, radioactivity, and states of matter.
The great thing about Elemental is that it is also a Universal Binary.