There is a floor tile in the middle of the living room background wall. Will the use of diamond-shaped decorative mirrors on both sides and above affect Feng Shui?

It doesn't matter much in the living room. Making a mirror can not only increase the light sense of the room, but also make the room feel a lot of space. You can install some fashionable shapes or patterns.

Generally speaking, feng shui is not good, and mirrors cannot be installed to reflect bathrooms, kitchens and other places, nor can they face the bed in the bedroom.

I hope my answer can help you.