amethyst

So as to receive the most reward that your new crystals can offer you should cleanse them right before using them. Most crystals take in energies, plus your new crystals happen to be taken care of by numerous people before they found their way to you. Who is familiar with what they've 'picked up' on their journeys?
If you inquire twenty people how they cleanse their crystals you're likely to receive 20 unique responses. Me? I like simple. I cleanse mine by immersing them in running water and visualizing any residual energies staying whisked absent. I like to use true streams as often as I can, but in the pinch you can run them under water out of your kitchen sink, or anyplace else where you can focus undisturbed�� to get a few minutes.
Like I said - I like quick.
So - now you have some very pretty stones that are clean and ready to be re-charged. Yet again, I like easy so more often than not I leave them to dry from the sun and/or moon (full-spectrum lighting works as well) for 50 percent each day or so. Alternatively, you can soak them in a very bowl with bouquets, like rose petals or carnations for 24 several hours - the crystals' negativity is removed and it is actually charged with the plant essences.
On the other end of the spectrum, when I'm going to be using a stone for any major undertaking (like therapeutic, or as an offering) I charge them with each of the 4 components: Earth - by burying* from the earth or in sea salt or soaking in sea-salt water (warning - salt isn't safe for all stones - Lapis Lazuli, Halite, Malachite, Selenite, Turquoise, Hematite, Opal, Pyrite and doubtless some others can be destroyed by salt - when doubtful err on the side of caution); Air - by exposing to incense or through smudging; Water - by soaking inside of a normal water source, or in bottled water inside of a pinch; Fire - by passing through smoke from the fireplace, or from a candle inside of a pinch.
OK - you have your cleaned and billed crystals. All that's still left would be to tell them what you count on them to do. Let's go back to 'easy'.
Look for a place where you can sit undisturbed to get a couple minutes. Obvious your mind of the happenings of the working day. Think about what you wish your crystal to do. Keep your crystal among your arms, rolling the crystal back again and forth several times. Then hold the stone to your encounter, inhale deeply through your nose, then exhale slowly through your mouth, onto your crystal.
References
Crystal healing
https://en.wikipedia.org/wiki/Crystal_healing