Vintage black stone in gold plated intricately carved cufflinks

These cufflinks feature an oval black stone (may be onyx) set in a gold plated intricate textured rectangular border. The border is bark-like or filigree. They have a Bullet backing. Bought between 1960s and 1970s by my husband's grandfather. Most likely to be Swank brand. Would go nicely with black tie formalwear. Must be able to come to my home to pick up.