The sample return canister from the Hayabusa spacecraft has been opened, and does contain a small amount of dust particles, according to the JAXA website. This is very encouraging news! However, it is not yet known if the dust is from the asteroid Itokawa, where Hayabusa briefly touched down, or if it could be from Earth — left in the container from before launch, or it possibly could have made its way in there during the landing/post landing handling. “Material on the planet or asteroid or particulate matter is at this stage is unknown, we will consider in detail,” is the Google translate version of the JAXA press release. According to Emily Lakdawalla at the Planetary Society, the dust grains are extremely small, about 0.01-millimeter in size, and there are about a dozen of them inside the container. This image was taken on June 28, 2010, and below is a magnified view of one of the particles.
This magnified view was taken on June 29, and shows a magnified view of one very small particle being picked up by a quartz manipulator, which appears as a stripe on the image.
It likely will take several weeks to confirm whether the particles are from the asteroid, but if so, would be the first-ever asteroid sample return.
Below is an image of Earth that Hayabusa took as it approached the home planet.