This occurred while I was still a baby in the crib so while I did not experience it directly all the other members of my family witnessed the following events.
It was 1968 and my family lived in a wealthy neighborhood in Houston, Texas. My grandmother on my father's side had been living with us for several years. About two weeks after she died something very strange occurred.
My mother was walking down the main hallway in our house and glanced into the large gold flake mirror at one end. She was shocked to see my grandmother's face on the surface of the glass. The image was not a reflection, but rather looked as if it was made of fog.
My mom immediately got my two brothers and my sisters to come look at the mirror. The image remained and they all saw it. Next, my mother called my father at work and asked him to come home. When he arrived his mother's face appeared on the mirror. It did not move or communicate in any way. It just sat there.
My father got a rag and wiped over the face. It wiped away like the smudge of someone's fingerprints.
Nothing like this ever occurred again, but when I grew older the same mirror hung in my room and I used to routinely turn it to the wall.