Diamonds, well known for being utterly useless piles of carbon atoms, may in fact be good for something: flaws inside them have been turned into an operational quantum computer.
Quantum computers are just like regular computers in that they crunch numbers using zeros and ones. The difference is that quantum computers manage to crunch numbers using both zeros and ones at the same time, which is impossible. But, "impossible" doesn't really apply in the quantum universe, where things have no trouble being more than one thing at once. This quality makes a quantum computer much better at solving specific kinds of problems involving looking for small things in large amounts of data.
This particular quantum computer (constructed by USC Viterbi) is solid state, meaning that it uses quantum bits (qubits) in a solid matrix instead of in the form of a gas or a liquid. The solid matrix in question just happens to be a one millimeter chunk of diamond, and the qubits inside are two little impurities: a nitrogen atom, and a wayward electron. Together, these little qubits were asked to find an item in a randomized list of four items, which (statistically) it should have found on its second guess most of the time. But, the qubits nailed the right choice on their first try 95% of the time, which is what quantum computers are good for.
The other cool thing about this diamond quantum computer is that it includes active decoherence protection, which apparently uses microwaves to "time reverse" the inconsistencies in the motion of the qubits. Don't understand it? Don't worry: rumor has it that nobody understands quantum mechanics.