Many crystals are harmed from the Sun! Some need Moon or just visualization.
Most crystals do not need to be purified as they already are, they come from nature. No need to purify unless a toxic person has been handling it.
To the OP: To program a crystal, it's the same as programming your aura. Tune into the crystal, feel it, and state your intention of what you want it to do. You can use runes too, but this is not always needed.