I quote "A mirror might look silver because it's usually depicted that way in books or movies. However, it's actually the color of whatever is reflected onto it. A perfect mirror has specular reflection, meaning it reflects all light in a single direction equal to what it receives."
Source: https://www.livescience.com/34427-what-color-is-a-mirror.html
p.s. I wanted to thank you for upvoting my latest post and thought of saying thank you; post upvoted & followed.
Absolutely correct, and it is therefore the colour white, since we perceive something to be 100% white when all the frequencies are reflected and no frequency is absorbed by the material a perfect white light is signing on. The sun is a source that creates perfect white light.