My magical system is based off of a ew chapters in one of those books. The spell crystal idea was a continuation of that.
I actually spoke with Midkemian Press for permission to use and adapt that system. They didn't want it as it only showed up in two chapters of a side plot in a book. Something they actually forgot about. The person I corresponded with said he had to go read the book in question to remember what I was talking about.
In the basics it is similar but I have adapted it and altered it far enough to make it different by far. Part of the reason they didn't remember it. So yes you found me out. But I have permissions to use. Go to Comment
I always liked this one. I used to represent this in game by getting dice in the appropriate size and when someone found one or used one the dice would exchange hands. I would then have them keep them in their pocket or a small dice bag to give the idea of carrying them and the amount of space they take up, that while they are small, they do take up space in numbers.