That dance includes all of life. All crystals give us an opportunity to move beyond an observer status. Beautiful as they are to look at, their true power becomes available to us when we enter into relationships with them. I've noticed, for example, that quartz crystals which originally came to me in cloudy condition get more clear the more attention I pay to them. On the deepest levels they are mirroring my own increasing clarity, which includes the clarity of my interactions with them.
Clusters are especially helpful.
They're a dance within themselves. Hold and study a cluster and notice that none of the points seem to be avoiding each other. Notice that rejection doesn't exist in the mineral kingdom. We can't be consciously part of the dance unless we know when we're out of step. Foremost among these is black obsidian.