Look for Micro-Meteorites
Spread out a plastic sheet across your backyard for a day. Also wipe the dust off plant leaves onto your sheet. The dust on it will contain some micro-meteorites. Now use a magnet to separate the magnetic specks from the rest. Examine these closely with the magnifying glass or a microscope. If the dust is magnetic and is dark in colour and has a rough pitted surface, it very likely is a micro-meteorite, and may be as old as 4 to 5 billion years old.