Luma Dice are carved from a single block of aluminum and feature different color LEDs for each side. Each die uses an accelerometer to detect motion so the light goes on when in use and turns off automatically. Plus, the battery inside is easily replaceable (and cheap).
And yes, they claim that great care was taken to keep the dice balanced.
Luma Dice blew away their initial Kickstarter goal almost immediately, but stretch goals include cool things like different color dice and even a D20 version.
Check out the project video below to see the dice in action.