Opal is a precious gemstone known for its stunning and unique play of color, which makes it unlike any other gem. Unlike most gemstones, opal doesn’t have a single crystalline structure; instead, it’s made of tiny spheres of silica that diffract light, producing flashes of multiple colors called “play-of-color.” No two opals are exactly alike — every stone has a completely unique pattern and color display, which is why they’re so special in luxury watches and jewelry.

Opal is a natural gemstone, meaning no two dials are ever the same. The play of colour — from soft pastels to deep blues and greens — changes with the light, making each watch unique. Piaget has embraced opal (along with other hard stones like jade and lapis lazuli) since the 1960s, weaving its beauty into both vintage and modern collections. 

This tradition of using stone dials isn’t just about aesthetics — it’s a hallmark of Piaget’s dedication to craftsmanship. In the 1960s and 1970s, the maison pioneered the use of ultra‑thin movements paired with delicate hard stone dials, a bold move at the time that helped define its identity as a maker of elegant, artful watches.