Selenite

Selenite is a popular crystal when it comes to cleansing and clearing the home or office space. It dispels negative energy and enhances clarity, focus and creates calm in any space. 

Not only is selenite believed to carry potent energy that can provide protection and improve well-being, it's also said to cleanse unwanted energies from your surroundings.  Some would say to place a piece of selenite above the doors that leads you to outside for protection of all who enters and leaves the house.