Scientists have recently confirmed that over 15 pounds of rock collected in Morocco fell to Earth from Mars during a 2011 meteorite shower. This is only the fifth occurrence of Martian meteorites falling to Earth, the last being 49 years ago.

These 15 pounds of rock matter are a relatively large addition to the 240 pounds of Martian matter known to have entered Earth’s atmosphere. Neither NASA nor Russian spacecraft has been able to return pieces of Marsm so the only examinable samples are those that have fallen as meteorites.

“It’s Christmas in January,” sad a former NASA sciences chief, Alan Stern. “It’s nice to have Mars sending samples to Earth, particularly when our pockets are to empty to go get them ourselves.”

Earlier this week scientists used chemical tests to determine the origin and age of the rocks. It has been theorized that millions of years ago something collided with Mars, sending rocks hurtling through the solar system before they reached Earth’s atmosphere, breaking into much smaller pieces.

This discovery of Martian matter excites scientists because they were found only six months after the meteorite shower. Most other discoveries have been found millions of years—or at the very least decades after they landed, making them susceptible to contamination.

“It’s incredibly fresh. It’s highly valuable for that reason,” said Carl Age, director of the Institute of Meteoritics. The samples were held by dealers who uncovered them. They are now selling them to NASA and other scientific agencies for a hefty price—up to $22,500 an ounce.

Many are hoping that NASA and the European Space Agency will team up in 2018 to send robotic spaceships to Mars that can collect and bring back rock and dirt samples so that we may know more about our mysterious neighbor.