does this sound like a copy?

ok so my friend and i were making up walang tiyak na layunin stuff, and i made up this rock and she says its a copy of a witch light from the Mortal Instruments, sa pamamagitan ng Cassandra Clare. if you don't know the series(City of Bones, City of Ashes, City of Glass, City of Fallen mga kerubin and madami coming out with the prequel Clockwork Angel, Clockwork Prince and madami coming) a witch light is a stone that basically glows to give off light. i made this up and she sinabi its a copy and i would like your opinion.
Here is the thing i made up:
"A rock the size and shape of a golfball. Its dark blue and has a blue glow to it. It was created sa pamamagitan ng witches in order to...." I call it the Larimar stone
and thats as far as i got it doesn't have a power yet, i still have to think of one so if you think of one while answering let me know. it has to be something important, that good and evil would want.(don't ask why we were doing this, we were stuck at a restaurant and decided to do this idk lol)
this is how i got the name of the stone if you care
link
thanks you guys! :)