I can't come up with a title off the top of my head, but I'm going to do something looking around. If these aren't a series that we have, it sounds like something that we'd like (and therefore ought to have). We have quite a few current and older children's book. (In our house quite a few= a few thousand. Literally.)
If you have more clues, it would help...
You said you read it in 6th or 7th grade. Do you remember if it was the larger format paperback for children (larger pages, but less pages), like Animorphs or Goosebumps, or if it was the smaller format, for young adult novels, like adult paperbacks are? (Might seem nonsense that I ask, but it actually might help finding them.)
Do you remember where you got/borrowed them from? Did your classroom teachers have them, or the school library, or do you remember seeing them in book club flyers from school? (Might indicate a Scholastic series...)
If the colored stones they had weren't rings, what kind of jewelry did they have them in or how did they wear/use them? And were the kids named for the stones, like Jet, Sapphire, etc? (And no, I can't think of that series at the moment, but don't think it's right, as I'm pretty sure it isn't "modern" but alternate world... and those were forehead stones.)
How old were the kids, and were they from the same family or different families? If you can't remember an age range, do you think they were younger, older, or able the same age as you were at the time. (We often have an idea of that, even if we don't realize it.) Were the books fairly innocent, such as what is written for grade-schoolers, or were they geared more toward teens?
Oh, and do you remember if they were new at the time, if new books in the series were coming out at the time, or if they happened to be a "fad" at the time?
(yes, lots of questions, but I'm hoping for things that will jog my and my sons' memories, partly because I want to see them, if we don't have them.)
