Columbia Mine (April Fool claim; Belo Horizonte claim; California Gem Mine; Columbia Gem Mine; Desert Rose claim; San Jacinto Gem Mine; Discovery), Thomas Mountain, Thomas Mountain [town], Cahuilla Mining District, Riverside County, California, USAi

Regional Level Types
Columbia Mine (April Fool claim; Belo Horizonte claim; California Gem Mine; Columbia Gem Mine; Desert Rose claim; San Jacinto Gem Mine; Discovery)	Mine
Thomas Mountain	Mountain
Thomas Mountain [town]	Town
Cahuilla Mining District	Mining District
Riverside County	County
California	State
USA	Country

O Columbia! the gem of the ocean,
The home of the brave and the free,
The shrine of each patriot's devotion,
A world offers homage to thee;

—David T. Shaw & Thomas a'Beckett. Lyrics from the song "Columbia, the Gem of the Ocean", (1843).

Setting:
The Columbia Mine is the oldest gem tourmaline mine in California, and is located in the SW¼SW¼ sec. 1, T7S, R3E SBM, 2.9 km (1.8 miles) S of Thomas Mountain (town), on the SE ridge of Thomas Mountain (summit), and 11.8 km (7.3 miles) ENE of Cahuilla (town). The mine workings are situated approximately 200 feet NE of Thomas Mountain Road, near the summit of the divide at an elevation of approximately 5,143 feet AMSL. MRDS database stated accuracy for this location is 100 meters.

History:
James Hamilton^[1] is credited with the first recorded discovery of gem tourmaline in California. Hamilton discovered tourmaline on the southeast slope of Thomas Mountain in June of 1872. Some mining was done at this point by Hamilton, and many gem tourmaline crystals were obtained, including a fine specimen acquired by George F. Kunz prior to 1873.

In 1893 serious mining efforts were made developing the deposit. In that year, both the California Mine and San Jacinto Mine were opened along the ledges to the southwest and northeast of the Columbia Mine, and some of the finest tourmaline crystals in the world were recovered. It was reported that many "float" crystals of colored tourmaline were found along the surface, with some of the largest crystals measuring up to 9 inches long. More than a bushel of fine gems was recovered that first year, including a beautiful red and green crystal eight inches long that was purchased by Harvard University. Another fine specimen was bought by the American Museum of Natural History in New York.

Kunz described the deposit at that time as a pegmatite vein ranging from 40 to 50 feet wide, and trending north to south through the old crystalline rocks which make up the mountain range. The vein was described as in some places consisting of pure feldspar, or feldspar with quartz, and at other points consisting of all mica, or rose quartz and smoky quartz. The tourmalines were described as varying in size from micrograins to crystals 4 inches in diameter, occurring mostly in the feldspar, but also found in other portions of the vein, sometimes in pockets or isolated. The larger crystals were said to generally have a green exterior with red or pink centers (var. watermelon tourmaline). Some of the other crystals recovered were said to contain green, red, pink, black, and intermediate colors (var. polychrome tourmaline), while others were a uniform tint of red (var. rubellite), pink, colorless (var. achroite), or blue (var. indicolite). Kunz described the associated minerals as rose quartz, smoky quartz, asteriated quartz, and fluorite, with some quartz having penetrations of fine hair-like crystals of tourmaline similar to rutile.

The Riverside Press (January 12, 1897) reported that the tourmaline mine owned by "Messrs. Jackson and Whiting in the Tahquitz district" were recovering some valuable gems. "Two specimens just taken out measured 1 1/2 by 2 1/2 inches each and are valued at about $400 each, as they are very valuable for ring settings, pins, etc. The color of these stones varies from a dark green to a deep amethyst." The report continues by stating "The largest tourmaline stone ever found in the world was taken out of this mine by Mr. Chilson and placed on exhibition at the World's Fair, where it took the premium. It was afterwards sold to an Englishman for $500."

In 1905, Kunz described the Columbia mine as being owned by H. C. Gordon, P. E. Johnson, J. C. Connell, and William Dyche of San Diego. According to Kunz, work had ceased at the mine around 1899, and only the minimal required assessment work had been accomplished over the following five years. Kunz hypothesized that the gem pockets may have been exhausted, as "nothing important" had been found recently. Elaborating on his 1893 description, the deposit was detailed as ledges of pegmatite consisting of a fine granite, with both sides of the pocket material seemingly identical in character, which was said to differ from any other mine yet found in the gem districts of California.

In 1959, John Sinkankas reported that any attempts to reopen the mine had enjoyed only limited success. On August 15th, 1982, a new lode mining claim was located by Jim Sherman, named the New Columbia #1. Another lode mining claim was later located by Sherman on January 8th, 1983 - forming a contiguous group of claims, and sequentially named the New Columbia #2. On September 28th, 1993, Sherman transferred his interest in both claims to Matthew C. Taylor of Vista, California. On September 1st, 1997, Taylor, together with J. Blue Sheppard of Pala, and Lee E. Humiston of Seal Beach - located the Belo Horizonte No. 1 and Belo Horizonte No. 2 lode mining claims, adjacent and contiguous with the New Columbia #1 and New Columbia #2 lode mining claims already owned by Taylor.

Under Taylor's ownership, several large open cuts and trenches were made to expose the old workings, utilizing heavy equipment including wheeled backhoes and loaders to remove overburden and decomposed rock. Several good sized pockets containing superb gem-quality elbaite crystals have been encountered throughout the excavation process. Some of the larger tourmaline crystals recovered were considered typical of the locality, with specimens of apple green exteriors with deep red centers that rival the finest known examples of such occurrences worldwide. The modern exploration of the site has been systematically documented by Taylor throughout his ongoing geophysical and mineralogical studies of the deposit. According to Taylor, the Columbia pegmatite is atypical of the region due to a nominal amount of mica group minerals present in the elbaite-bearing pocket zone of the dike.

Mineralogy/Geology:
Local rocks include Mesozoic granitic rocks , unit 2 (Peninsular Ranges).

Development:
Workings include unspecified underground openings.

Other Databases

Link to USGS MRDS:	10115556

Other Regions, Features and Areas containing this locality

References