06/22/2026
Exceedingly rare Arizona cinnabar nugget!
Arizona has historically been a very minor player in domestic mercury production--ranking behind California, Texas, Nevada, Oregon, and Utah. Several mines in the Mazatzal Mountains dominate Arizona production, followed by the Phoenix Mountains occurrences in Phoenix, and lastly from the virtually unknown Cinnabar mine at Cinnabar (ghost town) in La Paz County (formerly located in Yuma Co.).
The Pinal Geology and Mineral Museum has the following specimen in its reference collection; namely, a 120+ year old cinnabar nugget with some malachite staining in schist from the Cinnabar mine, located about 8 miles southwest of Quartzsite, Arizona. The label style and DM number on the piece can be traced to what is now known as the A.E. Seaman Mineralogical Museum in Houghton, Michigan. I've had many old de-accessioned AESMM specimens that carry such labels---they are very distinctive.
https://pinalgeologymuseum.org/
https://museum.mtu.edu/
The specimen is from the Michigan College of Mines and shows the Colonial Mining Company as the operator of the mine. The mine is associated with Parker on the label perhaps because this was a close arrival and departure town on the Colorado River. The donor is listed as Dr. F.W. McNair--he was the Michigan College of Mines President from 1899-1924. The school didn't become Michigan Technological University until 1964.
The Colonial Mining Co. operated the Cinnabar mine, discovered in 1861, from 1904-1908 and was replaced by the Cinnabar Development Company in 1908. This places the collection of the piece between 1904-1908 when there actually was a settlement of Cinnabar that served the mine and its workers. The mine finally closed in 1914 after unsuccessful attempts were made to de-water the mine. When CMC owned and operated the mine, the ore ran to a bit over 7 pounds of mercury to the ton and total production is estimated to be between 116-140 flasks of mercury. Each flask at that time weighed 76 pounds.
The ore was found in veins that ranged from a few inches to 5-6 feet in width and the best ore was found in the center 2 feet or so of the largest veins. Associated minerals were gold, malachite, metacinnabar (present on this piece as dull black material), tetrahedrite (mercury-rich), and wulfenite. In fact, there are references to cinnabar with gold and cinnabar with wulfenite crystals present in the literature! The cinnabar is believed to have originated as a product of the mercurian tetrahedrite which was also silver-rich.
A 30-ton brick Scott Furnace was built to treat the ore but the brick readily absorbed the mercury, reducing the efficacy of the furnace and hindering maximum mercury production. In addition, a 3-ton retort was built on the property. This would heat the mercury so that it converted to a gaseous state and then cooled to produce liquid mercury while leaving behind any solid gold. These structures are still present on the property. Access to the ghost town of Cinnabar is restricted owing to vandalism and a permit must be obtained prior to any visit.
It is believed that about $150,000 was invested in the mine and it returned but a $6000 profit. No doubt, the absorption of mercury by the locally made (on the Colorado River) brick and the high cost of timber (brought from California and Oregon and later from Arizona) coupled with transportation costs terribly handicapped this remote mining camp.
The specimen measures 1.21 inches or 3.07cm across and was gifted to the Pinal Geology and Mineral Museum by Dr. Raymond Grant (raygrantite)--the museum founder
This will be used in a future Arizona Mercury Mining display to be constructed at the Pinal Geology and Mineral Museum in Coolidge, Arizona. See less
