How far apart should incompatible crystals and minerals be stored?

[Recycler1337]

Let's say I have a small collection that I use for chakra work, meditation, runic work, etc. Some of them are incompatible, like black tourmaline. How far apart should they be during meditation and work? Let's say I have hematite on my table and I decide to meditate with charoite for my crown chakra. Is a distance of one meter sufficient, or will the hematite overwhelm the charoite and I need more? Is it even bad to keep them next to each other on the same table?