Troika

In a not so distant future, scientists find very special stones on another planet. If you collect three matching stones, you can turn them into an extremely valuable gem or into fuel. After hearing about the stones, you decide to travel to this new planet to become rich. You arrive safely, but after having some troubles on the way, your spacecraft is now out of fuel. What a dilemma! You want to make valuable gems, but you also need fuel to get back to Earth. You're also not the only person with this idea. Can you collect more gems than the others and still escape from the planet?