Take away all the metaphysical hype, and you have a very specific crystalline structure that vibrates in a unique way. Their vibrations interact with the vibratory field around them.
Crystals are essential to this process. Not only does the crystal matter, but also where it was formed and, if it gets very detailed, how it was mined and other odd factors. I’ve found that saying smoky quartz dissipates negative energy isn't enough; you need to understand what each crystal does best.
Some people can do this. I personally cannot. I’ve felt energy from crystals before on occasion, but it’s not something I can do regularly or with much consistency. General descriptions, like Rose Quartz for love, are usually correct, but the best energetic use of a crystal depends on the specific crystal itself. Unless you’re one of those who can determine this, one will be guessing in the dark like the rest of us.