As a solid color, silver is usually equated with gray, which can be achieved by mixing black and white. Silver usually has a lighter shade, however, compared to the latter. To replicate silver's metallic tone, mix shades of grays (or mix them with white) to create a silver gradient.
Metallic silver is not a true color in the sense that it is not a solid color. It's a reflective color tone that is only achieved by using metallic or reflective pigments together with the base color, gray, or by unevenly mixing various tones of grays to create a shiny effect. The silver color is often associated with first runner-ups in competitions.