It’s August, and you know what that means! The spotlight is on peridot – August’s lovely green birthstone, and one of Eastern Arizona’s claims to fame. 

Peridot on basalt or lava rock

Let’s talk about some of the most interesting geological facts about peridot. It is a type of olivine, which is the primary mineral found in Earth’s red-hot mantle. Once olivine makes it to Earth’s surface – usually through volcanic eruptions – it becomes unstable. For this reason, olivine is rarely gem-quality, and when it is we call it peridot. Most of the world’s peridot is found on the San Carlos Apache Reservation in Eastern Arizona. This is where – millions of years ago – there was a violent volcanic eruption. The lava flows brought nodules of peridotite with them. When the firey magma cooled and hardened, it formed black basalt (lava rock), much of it ornamented with peridot crystals. Have you ever seen a lava rock crusted with peridot? Well, now you understand why they form that way! 

Comet particle containing peridot collected by NASA’s Stardust spacecraft

Perhaps one of the most intriguing aspects of peridot is the fact that it’s also found in space. In 2004 a NASA space probe named Stardust collected particles from the comet Wild-2. In 2006, the samples were sent to Earth via parachute. After years of study, NASA published its findings. They found that some of the particles contained peridot. The materials studied are “primordial material unaltered by the violent birth of the solar system,” reports Science’s Richard A. Kerr. In other words, peridot has been around since the very beginning of the universe. Talk about ancient! 

USA, Arizona, Peridot Mesa. California poppies in bloom.

For many years, the Peridot Mesa in San Carlos, Arizona has been excavated by Apache miners. The jewels were used solely by tribal members in art and adornments until 1904 when the mesa became widely recognized as a fertile source for gemstones. It was mined and traded fervently until 1909. Today Peridot Mesa is mined sporadically by tribal members who have exclusive rights to the area. Currently, an estimated 85% of the world’s peridot comes from San Carlos, where it’s pronounced para-DOT and not para-DOE. It’s really no surprise that this sunny green gem is meaningful to the San Carlos Apache people!  

If you’re curious about peridot, stop by the Pickle Barrel Trading Post! Here you’ll find knowledgeable staff who can guide you to some of our most cherished peridot goods! We carry a variety of items including standalone peridot crystals, peridot on basalt, stunning peridot jewelry, and handmade peridot crafts and decor!