This is one of our favourite crystals at Lightworker Candles and Crystals. Selenite is a calm stone that installs deep peace. It has a cleansing effect that removes negative influences of all kinds. Selenite constantly recharges and cleans itself. It can cleanse, recharge and programme your crystals and gemstones. 
Selenite is very soft and brittle in nature, so be gentle with your crystal, making sure not to get it wet, as Selenite is water soluble