Vintage Vintage Textured Industrial Shiny Elegant Links

No maker’s mark Beautifully made cuff links Silver tone stamped textured metal with a shiny cabochon. I suspect the cabochon is some kind of glass. It looks like hematite but it doesn’t have the heft I would expect from a real stone. Approx: 3/4 inch diameter Great vintage condition! The mechanisms on the back are in great working order but so have a few spots of wear, see last photo. The fronts are excellent though!