The Largest Peridot in the World

The largest peridot in the world belongs to the Smithsonian National Museum of Natural History. It weighs an astonishing 311.8 carats. Photo by Public Resource.Org, CC by 2.0. Photo taken 2004.   Peridot rarely grows as large as 300 carats, so the discovery of one greater than 310 carats marks a special occasion. Indeed, the largest peridot ever discovered weighs an astonishing 311.8 carats. It belongs to the Washington A. Roebling Collection at the Smithsonian National Museum of National History.  

Washington A. Roebling

Washington Augustus Roebling (1837-1926) made his living as a bridge builder. His father, John A. Roebling, moved to Pennsylvania from Prussia with his designs for a wire rope made of steel. With these steel cables, he and his sons established a bridge-building business on the east coast of the United States. Eventually, the Roeblings relocated to Trenton, New Jersey. During the 1860s, Washington and his sons began designing and building the Brooklyn Bridge. Construction started in 1869 and carried on until its completion in 1882/1883. In the middle of the project, in 1872, Washington developed a debilitating case of the bends after remaining in a caisson for too long. A caisson is a watertight chamber with an opening at the bottom. By use of air pressure, the water is forced and kept out of the chamber so builders can work underwater without being submerged. Though unable to physically work on the bridge following this accident, he supervised his sons through to its completion. Bridge building clearly captured Washington's attention and passion. However, he had a second passion, as well. Collecting mineral specimens. His interest in minerals piqued in the mid-1850s, while he attended Rensselaer Polytechnic Institute. Over the ensuing years, he managed to amass a collection of more than 16,000 minerals, gemstones, and meteorites. He obtained at least one of every mineral species available for acquisition. Following his death in 1926, his son John Roebling, II, donated the entire collection to the Smithsonian Institution. His son also gifted the museum with $150,000 to maintain and expand the collection.  

The Largest Peridot in the World

With the endowment, the Smithsonian has added no less than 13,000 specimens to the original collection, bringing the total to nearly 30,000. The Smithsonian labeled the original mineral specimens with catalog numbers R1 to R6000. The remaining 10,000 specimens represented gemstones and meteorite specimens, rather than raw mineral specimens. Amid this vast collection lies the largest known peridot in the world. Weighing in at 311.8 carats and cut in a mixed cushion shape, the Smithsonian catalogs it as NMHN G3398-00 (MIN). According to the Smithsonian's record, the peridot originated from Zabargad Island (St. John's Island) in Egypt. They describe it as a primary gem with a dark slightly yellow green coloring. The Smithsonian lists its former catalog number as R00008. Could it be that this gorgeous peridot belonged to the original 6,000 mineral specimens belonging to Washington A. Roebling? Further research is definitely required to answer that question. So I sent an email to the current archivist for this specimen. When I hear back, I will return and update this article. ~Angela Magnotti Andrews