Random gift of nature? or something else?

when I was younger, I had just moved into an old house, with a vast backyard that was overgrown. Huge trees towering over all area houses. My parents were working on clearing brush, and I as in my nature, was exploring. There were some roofing shingles stacked beside the door. And underneath, was yellow crystal. Just suddenly there. such a strange thing. I thought I was just lucky, though I had always believed in the fae, and other such beings. But this is where it becomes less of a coincidence. My younger sister had left her shoes outside overnight, and the next morning when she went to retrieve them, she found amythest of the same size in her shoe! I know a skeptic would say it was our parents, but it couldnt have been. they were angry and thought we had stolen them from a collection they had gotten from the smokey mtns. and our neighbors were a very old antisocial man, and a family that didnt ociate with us. So, where could they have come from? and why? I know there must be someone who would know.