Although I'm very much a traditional jewelry kind of gal, I'm strangely drawn to the M3 and M4 rings. I think it's because they are sleek but still pay homage to typical tool hardware.
Designed by The National Design Collective, the M3 and M4 rings feature a pretty simple concept. Made out of sterling silver (not steel, as it appears), they are "cut to reveal screw threads," according to Yanko Design. They are sold for $180 each.