I watched a documentary about a guy in the colorado that lived in a haunted house and took pictures of his mirror. When he looked at the pictures, there were faces in the mirror. I decided to do this with my cell phone on night vision, there was a face but what freaked me out is my friends face that passed away in 2012 was right under the mirror. I didn't even take a picture. All I could say is her name and get out of the bathroom. Has anybody else had this experience?
Usually mirrors are made from glass and plastic. But there are certain old ones made from an older material, and it's maker can in fact trap certain energies within itself that can show themselves. I'm guessing you have a regular mirror that is plastic and glass, but may or may not have residue energy from your friend.
There is an old belief that one must cover all the mirrors of a house when a close one has passed away, as it is believed that they when walking through the house can become trapped in the mirror(it is a legend, thought I'd bring it up as it pertained to this). It is possible as stated above for certain energies to become entrapped within mirrors, it's nothing really to worry about.
The first man-made mirrors were polished metal. They did not reflect incredibly well (compared with more modern counterparts), but could be functional. They were expensive, so not many people owned one.
Later, people began coating one side of a pane of glass with substances. Metals became the norm for this, including lead in cheap mirrors and silver in expensive mirrors. I heard of murcury used in some cases. Today, a different backing is used (more of a metallic paint than any precious metal).
But those metals would corrose over time. The flaws within the incredibly thin surface may not be noticeable in bright light, or when other strong reflections are the focus of the person looking at the mirror. However, low light conditions, focusing at the mirror's surface, long-exposure near-dark photography, and the like, could make these flaws more apparent.