Question: what colour is a mirror?

Robert Woolfson answered on 17 Jun 2013:

Strictly speaking, colour depends on what light is absorbed by something. As a mirror reflects light completely (in theory), it has no colour at all.

However, most mirrors are a sheet of reflective glass placed over a silver backing. The glass isn’t perfect, it lets a bit of light through which is absorbed by the mirror, making most mirrors look silver.