As a form of divination, mirror scrying evolved from water scrying. Early man used his reflection in the water. Once mankind learned to create reflective surfaces, scrying was sure to follow.
Early mirrors were made of highly polished metal, mercury behind glass, and even obsidian. Modern mirrors are equally effective for scrying. The size of the mirror is unimportant, as is the type of mirror.
The shape of the mirror can affect the results. Traditionally, mirrors have been linked to the moon. Because of this, mirrors should be round or oval, rather than square. Mirrors that are backed with silver, or are contained within a silver frame, seem to be more powerful. Likewise, old mirrors work better than new ones.
Many seers prefer a black mirror, though these are hard to find. Early black mirrors were made of obsidian. Today, you can easily make a black mirror if you prefer to use one. Remove the glass from a frame and paint it black on one side. Add several coats of paint to ensure good coverage. Place the glass back in the frame, with the paint facing inward. This will provide you with a black reflective mirror which can be used for scrying.
When using a black mirror, it should be left on the table and viewed from an angle. Do not view your reflection in the black mirror. Look into its depths. At first you may only see shades of gray, but be patient. With time and practice, images will appear. Occasionally, spirits will also appear to look at, touch, and talk to the scryer.
Another form of mirror scrying involved receiving messages on the mirror. For example, messages may be received on a steamy bathroom mirror. You can achieve similar results by using a candle or flash light in a dark room. By holding the light at a safe distance below your face, you may see your reflection change and change again. Some believe that these images will show yourself in a past or parallel life.