According to BBC Science Focus, most mirrors are white with a greenish tint. In general, color is the result of reflected light. That is, in order to achieve one kind of color, some light waves must reflect others. For example, if an object looks red to a person, it simply means that it is reflecting red light. The mirror should reflect all colors, so ideally it should be white.
But in reality mirrors are not perfect. ZME Science states that many of them reflect green more strongly than other colors. This is because their substrate is made of quartz glass, and the atoms of this glass can reflect green waves more strongly than others.
When light hits an object, that light is either reflected, absorbed, or passed through the object. Because mirrors are very smooth, they can reflect light without scattering it.
Source: Ferra
