“My work has a subtle aggression,” says Ana-Katarina Vinkler-Petrovic, the local designer behind the AnaKatarina line of sustainable jewelry. Case in point: her new cuff links crafted from petrified mammoth and walrus tusks. How’d she come to create accessories fit for a stylish cave man? It all started on Christmas a few years back, when her kids’ gift of a book called The World of Rings left her wondering aloud about ethical alternatives to ivory during the holiday meal. Her own mom quickly chimed in. “She said, ‘Well, how about you use cow bone?’” the designer recalls. “I never thought of this before. I said, ‘What kind of bone would one use?’” Her mother answered matter-of-factly: “Well, the shin bone of course.”

After a Whole Foods trip, Vinkler-Petrovic got to work. “I started by using the bones that we give to dogs. I boiled them, got the fat out of them and started carving those.” Later, she began experimenting with sustainably sourced camel bone and mammoth and walrus tusks, pairing them with conflict-free gems and recycled gold in her jewelry. But she only recently started designing for men, debuting her first cuff links at Dubai’s fashion week in the fall. Now she’s at work on a second cuff link series, slated to launch in February. “They’re more influenced by midcentury modern design and the use of positive and negative space,” she explains. But that’s not all the designer has up her sleeve—she’s looking into a material even more macho than mammoth. “Right now we’re sourcing petrified walrus penile bone!” she says with a laugh. “I thought that was kind of fun for cuff links.”

Check out more designs at anakatarina.com