Selenite is a must have crystal for your crystal collection due to its cleansing energy and angelic properties.
 
Selenite is a self-cleansing crystal so you don't have to use any method to cleanse the energy of the crystal. By having this quality if you had a large enough piece of selenite you can use this to cleanse the energy of other crystals and minerals.
 
Selenite is also a crystal that resonates with the energy of angels, so when looking to connect to the angelic realm for answers, guidance and protection selenite will be the perfect tool.