Updated: Oct 2, 2020
By Alissa Young, GG
On behalf of Milstead Gems LLC
Imagine a gemstone mine. Is it deep within the heart of the lush Colombian jungle, where independent laborers brave treacherous conditions to dig for verdant green emeralds? Maybe it is a crowded streambed in Myanmar, teeming with artisanal miners panning for colorful pebbles of sapphire, spinel, and ruby. Or perhaps it is a winding open pit in Botswana, where excavators and drills circle deep into the earth in search of diamond-bearing kimberlite. For many, gemstone mining evokes images of exotic and distant lands. However, gemstones are found almost everywhere, including North America. For example, the United States of America is in fact a treasure trove of beautiful gemstones, from the coveted sapphires of Montana and rare red beryl of Utah to the cheerful green peridot of Arizona and glittering sunstone of Oregon. Perhaps one of the most fascinating and historically important mining regions in the country can be found in sunny San Diego, where pegmatite veins host a gemstone that occurs in nearly every color imaginable: tourmaline.
The name “tourmaline” is derived from the Sinhalese word toramalli, or “mixed gems.” Occurring in such a wide range of hues, the mineral was often mistaken for other gems like emerald and zircon before it was identified as a distinct species group in the 1800s (1). Among the most significant tourmaline species are elbaite, liddicoatite, dravite, uvite, and schorl, each with identical crystal structure but unique chemical and physical properties (2). Tourmaline is often further classified by its color, such as verdelite for green and indicolite for blue varieties. Stunning neon-hued gems from Brazil, their color caused by copper impurities, are often referred to as Paraíba tourmaline, while similarly-colored stones from other regions are identified as cuprian or copper-bearing. One of tourmaline’s most prized qualities is its strong pleochroism and distinct color zoning, which can result in gems that display two (bi-colored) or more (parti-colored) colors.
Although tourmaline had been found in other countries centuries before, it wasn’t until the gem was discovered in the US during the late nineteenth century that it gained true popularity. First, mint green tourmaline mined in Maine drew the attention of famed Tiffany & Co. gemologist and mineralogist George Frederick Kunz (3). When new deposits of top-quality green and vibrant pink-to-red (rubellite) elbaite tourmaline later emerged from southern California, the gem became an international phenomenon, gaining the attention of the Romanov czars and Queen Victoria of Great Britain. Empress Dowager Cixi (Ts’u-hsi) of China was among its most fervent admirers, ordering over 120 tons of gem-quality pink tourmaline rough from San Diego through Tiffany & Co. (4). The California tourmaline operation depended so heavily on trade with China that mining nearly ceased entirely after her death and the collapse of the Imperial government in 1912. The mines continued to be worked sporadically until the discovery of Brazilian tourmaline reignited interest in the gem in the 1980s (3).
The aptly-named Gem Hill of Mesa Grande hides an underground labyrinth of over five miles of tunnels that has produced approximately 250,000 pounds of material over the course of a century. Along with the fine pink gems that adorned the imperial court of Empress Dowager Cixi, green, bi-colored, and parti-colored tourmaline are all found in the renowned Himalaya mine, including the sought-after variety with a pink core surrounded by green known as watermelon. Roughly 5% of the material retrieved from the pegmatites here are considered gem-grade tourmaline rough, and the Himalaya tourmaline mine remains the biggest producer of California tourmaline (5).
The nearby Pala district hosts a number of smaller but equally significant operations, including the Stewart, Oceanview, Tourmaline Queen, Tourmaline King, and Pala Chief mines. Like Mesa Grande, this area produces a variety of quality pink, green, and multi-colored elbaite tourmaline, but some deposits have been particularly spectacular. In 1972, in what was referred to as the “find of the century” by then-curator of the American Museum of Natural History, the Tourmaline Queen revealed what would be known as the Blue Cap Pocket (6). With vibrant pink-to-red bodies and rich blue terminations, the pristine crystals recovered from the small pocket would become world-famous.
Even as new discoveries in Brazil, Madagascar, and around the world gain popularity, the exceptional tourmaline crystals found in southern California continue to captivate gem lovers. Although production is much smaller than it was during the hectic years at the start of the twentieth century, new beautiful gem-quality specimens continue to dazzle buyers. In the search for precious tourmaline, these San Diego mines have also led to the discovery of a new variety of spodumene, later named kunzite after the renowned mineralogist who identified it, as well as morganite beryl, topaz, and garnet (4).
Looking for tourmaline facet rough? Check out Milstead Gemstone's Tourmaline collection, including pieces from Himalaya Tourmaline Mine in San Diego county!
1. “Tourmaline History and Lore.” GIA. Accessed July 4, 2020. https://www.gia.edu/tourmaline-history-lore.
2. “Tourmaline Description.” GIA. Accessed July 4, 2020,.https://www.gia.edu/tourmaline-description.
3. “Tourmaline History.” American Gem Society. Accessed July 4, 2020. https://www.americangemsociety.org/page/tourmalinehistory.
4. “History of Mining in Southern California.” San Diego Natural History Museum. Accessed July 4, 2020. https://www.sdnhm.org/exhibitions/all-that-glitters/history/history-of-mining-in-southern-california/.
5. “Himalaya Tourmaline Mine.” High Desert Gems & Minerals. Accessed July 4, 2020. https://www.highdesertgemsandminerals.com/html/himalaya_tourmaline__mine_.html.
6. “The History of Pala Mining.” Pala International. Accessed July 4, 2020. http://www.palagems.com/mining.