Vintage four black metal attractive bowls

Two black metal serving bowls at 10” circumference And two larger black bowls with 13” circumference On the bottoms are three little feet of black metal balls The sides have a decorative ring of small black metal round studs. I don’t know what metal this is, but it does rust. So serve only dried food such as nuts in their shell, wrapped candy or napkins. I used it as a home for my collection of necklaces, bracelets, ribbons and vintage family photos. These shallow bowls look great in many decors. I have also used them at Mexican themed dinner parties. I will be slowly letting go of many turquoise dishes I used for these occasions. Very good condition, they are from Pottery Barn in 1990.