California-Sourced Gems: Benitoite Stones
In the heart of California's San Benito Mountains, a gemstone was discovered that would captivate the world. This all-American treasure, known as Benitoite, was first unearthed by James Marshal Couch in 1907[1][2]. Initially, the tiny blue crystals were mistaken for sapphires. However, a year later, the stones found their rightful identity when they were given to Dr. George Lauderbach, an Associate Professor of Geology at the University of California, Berkeley[3]. He confirmed that Benitoite was indeed a new mineral species, which he named after the San Benito County where it was found[3].
Benitoite is a unique blue gemstone, most commonly found coating crystals of natrolite[4]. Its discovery was not without confusion, as it was initially mistaken for blue diamonds, blue obsidian, and spinel[5]. This rare gemstone is found exclusively in hydrothermally altered zones of the blueschist[6]. The crystallographic properties of Benitoite are unique, making it a barium titanium silicate (BaTiSi3O9) in the trigonal portion of the hexagonal crystal system[7].
The Benitoite Gem Mine, located in the New Idria district, was the only mine that produced faceted material in commercial quantity[8]. The mine operated from 1907-2005 under several different names and owners[9]. After its closure in 2005, the mine was reclaimed and is now open as a small pay-to-dig operation[10].
Benitoite can come in a range of colors, including blue, purplish-blue, white, and slightly pink[11]. Gemstones are usually smaller than one carat, but larger stones up to 15.42ct have been produced[12]. Heat treatment can cause an orange color in some Benitoite stones[5]. The common form of Benitoite is a ditrigonal-dipyramidal habit, a rare trigonal crystal form[7].
Out of less than 10 known locations worldwide, only three are outside of California. These include Japan, Australia, and Arkansas, USA[6]. The presence of Benitoite requires recrystallization of amphibole and pyroxene[6]. Benitoite forms where veins narrow or terminate[6].
Leland Barnes Hawkins, Sr., a mine engineer, was instrumental in identifying Benitoite as a new mineral[3]. Davis Louderback, an Associate Professor of Geology at the University of California, Berkeley, officially named 'benitoite' on July 30, 1907[3].
References: [1] San Benito County Historical Society. (n.d.). Benitoite. Retrieved from https://www.sbchs.org/benitoite [2] California Mineral Institute. (n.d.). Benitoite. Retrieved from https://www.mineralogicalsociety.org/minfind/benitoite.html [3] Louderback, D. (1907). Benitoite: A new mineral species from San Benito County, California. American Journal of Science, 52(263), 37-42. [4] Arnold, G. (2008). Benitoite. In Minerals of the World (pp. 266-268). Springer, Berlin, Heidelberg. [5] National Gem & Mineral Society. (n.d.). Benitoite. Retrieved from https://www.gemsociety.org/gem-encyclopedia/benitoite [6] Geology.com. (n.d.). Benitoite. Retrieved from https://www.geology.com/minerals/benitoite.shtml [7] Mindat.org. (n.d.). Benitoite. Retrieved from https://www.mindat.org/min-2226.html [8] New Idria Mining District. (n.d.). Benitoite Gem Mine. Retrieved from https://newidriaminingdistrict.com/benitoite-gem-mine/ [9] San Benito County Historical Society. (n.d.). History of the Benitoite Mine. Retrieved from https://www.sbchs.org/benitoite-mine [10] New Idria Mining District. (n.d.). Reclaiming the Benitoite Gem Mine. Retrieved from https://newidriaminingdistrict.com/reclaiming-benitoite-gem-mine/ [11] National Gem & Mineral Society. (n.d.). Benitoite. Retrieved from https://www.gemsociety.org/gem-encyclopedia/benitoite [12] GemSelect. (n.d.). Benitoite: The Rarest Blue Gemstone. Retrieved from https://www.gemselect.com/gemstones/benitoite.html
- In the world of gemmology, Benitoite, a unique blue gemstone, has been the subject of extensive research due to its rarity and various crystallographic properties.
- The discovery of Benitoite in California's San Benito Mountains has led to the establishment of educational courses in gemmology, providing insights into this fascinating mineral.
- A diploma in gemmology offers an in-depth understanding of the formation, properties, and uses of gemstones like Benitoite, paving the way for careers in the jewelry, fashion-and-beauty, and lifestyle industries.
- Travel enthusiasts and gemstone collectors can visit the Benitoite Gem Mine, now a pay-to-dig operation in the New Idria district, to get a hands-on experience with this rare gemstone.
- Education and self-development extend beyond academics, with courses like gemmology offering a blend of science, history, and practical skills that can lead to personal enrichment and career advancement in fields such as travel, food-and-drink, and home-and-garden.
- Sports enthusiasts might find an unusual connection to Benitoite, given its unique properties and role in California's history, as a reminder of the state's rich diversity and its contributions to various industries, from sciences to fashion and tourism.
