Originally Posted by Astral Explorer

99%+ of the time a person lost or misplaced the crystals like any other object, or they were stolen by a person or animal. But there is definitely a very small probably less than 1% of instances where neither of those logical answers are applicable, and so in those remote cases we have no choice but to think outside of the box. I can speak from personal experience of losing about a dozen or so crystals that once you store your crystals somewhere safe and don't leave them sitting around on a table, floor, etc. they typically stop disappearing. So either cardboard has some magical multi-dimensional shielding properties or people are just clumsy and lose things, obviously it's usually far more likely the latter of the two.