This canister came from the Japanese spacecraft Habayusa, the first rocket to travel to an asteroid and back. It might look empty, but inside are dust particles that came from the asteroid . . . hopefully.
Although Habayusa did succeed in bringing back images and information from the near-Earth asteroid Itokawa, it's still unclear whether it managed to bring back any materials from the rock. Jaxa, the Japanese space agency, had bankrolled the 200 million dollar project, and they enjoyed pretty much nothing but trouble for their efforts.