Which stones NOT to use together?

Hello all! I haven't been able to find much on this out there, but are there any crystals that, used in combination with certain other crystals, will provide unwanted effects or are there certain types of crystals that just don't get along? I'm very curious to see if there are any!

I don´t know about unwanted effects but I think very strong ones (Kyanite etc) can easily overshadow crystals that are more subtle (Rose Quartz, Howlite, Aquamarine etc). I use Aquamarine a lot and I find it needs a lot of "space" so I generally use it without any other crystals.
Maybe this is also a case where size matters P)? I like to use the bigger chunk of Rose Quartz if I have other crystals in the same bowl with it. Otherwise I feel it gets overshadowed.

I've heard of this before, but I can't seem to recall the stones. Clear Quartz will produce an amplifying effect, so you may watch what you use it with. Herkimer Diamonds, Lemurians, Moldavite, Lithium Quartz, Auralite 23, Super 7, Yellow Serpentine, Rubies (large ones), Siberian Blue Quartz, Cherry Quartz, Garnets (large ones), natural Citrine, and Cocaxanite in citrine, are my short list of very strong crystals. I wouldn't suggest combining anything with these. You can always try whatever you wish, just note the effects. You can make yourself sick, so always pay attention. Too much Ruby or Garnet for me will shoot my blood pressure through the roof. Maybe others will have some more advice to offer.

I have not experienced any cases of "do not use together" in the general sense. Above all else, trust what your body and intution tell you.

As for different types of stones, I ask whether each would like to help, share my intention, and sense anything that comes. If my body feels good, the combination is good for that instance. Actually, I usually share my intention, then ask for volunteers. In that way, the stones offer me some great options for that instance. I regularly learn things and use stones I would not have thought of on my own. Asking this way bypasses the entire issue of unwanted effects and inappropriate combinations.

Individually, I have a crystal who loves to talk it up and get other beings talking with each other. Most stones, humans and animals readily play. However, I have a fire agate who for awhile, would physically repel the chatty crystal. I could feel my hands being pushed apart. That was my signal to leave things be and not work with those two together. Later they were glad to work together. Working alone with that fire agate taught me a lot about boundaries.

OT: Welcome to the forum stonesatiety.
You are welcome to post an introduction in New Members -but absolutely no pressure

I just did, then found your message. Sorry about that.

Nothing to be sorry about. Introduction is by no means required.