IOR: Index of Refraction app for iPhone and iPad
This application contains over 300 Indices of Refraction, with example images of the optical shift for each, and links to Wikipedia and Google searches for each material.
The Index of Refraction is quite useful when designing lenses, manufacturing optics, testing materials, or when simulating materials in 3D applications (such as modo, Maya, LightWave, 3D Studio, Softimage, Maxwell, Blender or POVRay) that make use of such techniques as ray tracing, and have parameters for entering the IOR.