In feng shui a mirror brings the energy of the water element. Because water that is calm and pure can always be used as a reflection.
There are three types of mirrors in feng shui:
The Bagua Mirrors are used to protect a house from harmful energy which may attack the occupants, also can be used in office and shops on front doors (outside) to deflect negative energy from poison arrows such us sharp edge of a building, tree trunk, any kind of tower, the angle of a roof line and any other offending structure facing at your front door. This eightsided symbol is very beneficial since its power comes from the trigrams which are arranged on each side of the eight sides. It is only used outside the front door of your house, office or retail store facing away from it.
The typical mirrors with any shape and frames. A round mirror with a golden frame is a very good and beautiful feng shui and a cure that will work very well in the SE feng shui area of your home.
The concave mirrors which are the ones that are most commonly used outside and produce and upside down condensed relection.