For this reason, I took video of myself walking on the field after the game. The photo in the listing is me posing at first base with my baseball glove and the Yankees hockey jersey (I live in NJ and went to the Yankees home game when they were giving away the hockey jersey as a promotion). I can share more pictures from my trip to Oakland/SF if you need more proof. An item like this cannot be certified unless MLB is doing it from their representative at each game. So I can't cert this with JSA or PSA or any others.
Each vial contains 1/2 an ounce. I also have another posting for dirt specifically from the infield.