Or anything metallic as long as it's dark.
Pewter is a metal, a slightly darker version of silver with a hue of midnight blue.
Hematite is a stone; imagine a sleek black mirror, shiny reflective and smooth.
Other names of similar colours are: gunmetal / gunmetal grey, midnight silver.
I also love bronze...
This is a pewter apple (Joseph Nero Modelmaking)
Hematite (Jonas Damon)
Bronze Tomb Panels (Joseph Nero)