Tesla ring18ct yellow gold Tesla ring with a bespoke oval cut Rubellite, which is flanked by two pencil designs, each with a Maya cut ruby. The underside of the ring features intricate triangular detailing, which homage to our signature cut. Most prominently though, the ring is engraved with the numbers 369. According to Nikola Tesla, a true rockstar of his time, this number sequence was the key to the universe; a code to initiate divine correspondence.