According to Google “Feng Shui is a system of laws considered to govern spatial arrangement and orientation in relation to the flow of energy (qi), and whose favorable or unfavorable effects are taken into account when siting and designing buildings.”
Feng shui is one of the basics of design which most designers learn about while in school, which studies the pshycology of human behavior within a room. This helps designers be able to identify the elements of feng shui that all create an atmosphere within a room.
Feng shui can sometimes include crystals and other elements that may seem a little “out-there”, but the important part of feng shui is not the elements added to a space, but how you feel within the space. In my personal opinion, I think adding crystals to a room can be a little “out-there”, but it all comes down to pschycology. If you believe that adding a crystal to your room will make you feel less stressed/have more money/have better health, etc. then you are giving the crystals more “power”, and it may work for you.