New Mexico Mineral Symposium
November 9-10, 1991
Metamunirite, haynesite, and other microminerals from the four-corners states
Patrick E. Haynes
Metamunirite is a new mineral which was approved by the International Mineralogical Association (IMA) in early 1991. It is an orthorhombic, anhydrous sodium vanadate. Munirite, with two waters (NaVO3 • [2-x] H20), is found as an efflorescent crust at Azad Kashmir, Pakistan. I assume that the munirite from Pakistan is locally stable or that the researchers simply did not describe the dehydrated, or meta, form. The type locality for metamunirite is the Burro mine at Slick Rock, San Miguel County, Colorado. It occurs as an efflorescent crust of very tiny white acicular crystals and is associated with metarossite (hydrated calcium vanadate), pascoite (another hydrated calcium vanadate), and thenardite (sodium sulfate) on vanadium-rich ore on the dumps. On April 6, 1986, I was collecting samples of pascoite at the Burro mine with Arnold Hampson. I found a corner on one boulder that had what I assumed to be a microscopically crystallized sulfate mineral. I collected the material, all of a few square inches of crust, and saved it for a few years. Repeated trips to the mine for pascoite did not yield any more material until November 5, 1989. On that day I collected a few square inches of white acicular crusts. I finally had 10 to 12 samples of the material so I sent one for analysis. The results were surprising, and subsequent trips to the mine yielded only one other specimen. Collecting at the Burro mine can be extremely frustrating because common crusts of white thenardite seem to be every¬where; an entire carload of potential metamunirite can turn out to be nothing but thenardite. So, only about 12 samples have been collected at the type locality.
In the summer of 1990 I had the good fortune to meet Mr. Phillip Allen. He arranged for a collecting trip in the Deremo-Snyder mine, San Miguel County, Colorado. On August 2, 1990, I met him at the mine and we took a skip down 700-750 ft to a waiting diesel-powered buggy. Mr. Allen had already located variously colored crusts of secondary minerals in the mine. We collected blue crusts of chalconatronite (its fourth world locality?), bright-orange pascoite crusts, and one and a half flats of what may become a new olive-green uranium mineral, Phil's potential first! I spotted an odd patch of white acicular material in a very rich vanadium horizon. It formed attractive acicular crystals and was associated with pascoite and rossite. The white material collected filled one flat, about 20 specimens. It turned out to be metamunirite that was much superior to the Burro mine material. Unfortu¬nately, the Deremo-Snyder mine ceased operating shortly afterward and the mine has been filling up with water. The colorful walls of efflorescent minerals are now under water.
In April 1991 I was in the vicinity of Naturita and took a quick look at the Long Park area, just north of Paradox Valley, Montrose County, Colorado. On the dumps of the Long Park #16 mine I found two boulders that had efflorescent white acicular crystals. They looked pleasantly identical to metamunirite. I collected about three quarters of a flat. Later examination showed it to be hexahydrite, a hydrated magnesium sulfate.
The Big Indian mine, south of La Sal, San Juan County, Utah, has been the site of azurite mining in the last 15 years or so. The microscopic arsenates have been mostly overlooked. Recent finds included drusy aggregates of fine-grained, sky-blue tyrolite. It resembles chrysocolla smears, and microcrystals have not been found. It can form relatively continuous coatings to 10x10 inches. Associated with it are flat round masses of black manganese oxides ("psilomelane") and occasional greenish-blue coatings of clinoclase. The clinoclase can liberally cover several square inches of surface, but unfortunately, like the tyrolite, does not readily form microcrystals. Some crystals have been collected, but it preferentially forms as aggregate coatings. Microscopic white acicular crystals of olivenite (var: leucochalcite) have been found associated with blue to green smears and spheres of cornwallite and microcrystals of azurite.
Haynesite was approved by the IMA in the summer 1990. It is an orthorhombic hydrated uranyl selenate and is found at the Repete mine in San Juan County, Utah. Marcelino and Marc Mendisco were mining uranium ore at the Repete mine in 1986. I snagged an invite to the mine and first visited it on August 2, 1986. I was looking over the high-grade ore pile and found three secondary uranium minerals. These turned out to be boltwoodite, andersonite, and haynesite. When the miners came out to dump some ore, I introduced myself. I pointed out to the miners some of their secondary minerals and asked if they could show me where they had gotten them. They gave me a mine tour and showed me the locations of the secondary minerals. They were extremely helpful.
About three months passed before I received analytical results on the material. It was microprobed almost simultaneously by Paul Hlava and by Pete Modreski. It was an apparent new mineral and I was able to visit the mine two more times to collect specimens before it closed in January 1987 because of caving problems. The high-grade pillars that contained the haynesite had been removed and sent to the mill. On my last visit I found one extremely poor sample of haynesite in the area where the ore had been stockpiled. Approximately 10 boxes and one 70-lb sample of haynesite had been collected.
On May 11, 1986 Arnold Hampson showed me where to find some things at the Monument #2 mine in Apache County, Arizona. We collected rauvite, metahewettite, tyuyamunite/metatyuyamunite, and several odd samples. Recently, I had some of the odd samples analyzed. One sample had microscopic black aggregates of bokite (a hydrated aluminum iron vanadate). Another had tiny golden-brown acicular crystals of fervanite (a hydrated iron vanadate) with very tiny dark-brown lustrous crystals of schubnelite (an iron vanadate hydroxide). This is apparently the only sample of schubnelite from elsewhere than Mounana, Gabon.
About December 8, 1988, Arnold Hampson and I took a quick look for zeolites on State Highway 78, 31/2 mi west of the New Mexico border in Greenlee County, Arizona. In the andesite flows of some of the roadcuts we found microcrystals of clinoptilolite, mordenite(?), and erionite.
In July 1990 Marc Wilson and I made two trips to the May Flower mine area on Socorro Peak, Socorro County, New Mexico. We found some microscopic minerals that had not been reported from this mine. These included linarite, caledonite, rosasite, anglesite, and fornacite. Nearly all of these minerals occurred as pretty poor samples, and they were all found in an approximately 1-ft3 vein breccia fragment. The surrounding breccia fragments did not contain these minerals.
Acknowledgments—I wish to thank Marc Wilson for allowing me to use the micro-photography equipment in his office. I wish to thank the following researchers for their help: Paul Hiava, Michel Deliens, Howard Evans, Jr., Marc Wilson, and Pete Modreski. I wish to thank Phillip Allen and the staff at the Deremo-Snyder mine for their hospitality. I especially wish to thank the Mendisco family: Marcelino, Marc, and their late father Felix, who granted me permission to collect at the Repete mine, but whom I was not fortunate enough to meet in person. I would also like to thank Will Moats for information about Socorro Peak and Ron Gibbs for information about zeolites along Highway 78.
- Fleischer, M. and Mandarin, J., 1991, Glossary of mineral species 1991: The Mineralogical Record Inc., Tucson, Arizona.
- Moats, W., 1991, Minerals of the Socorro Peak district, Socorro County, New Mexico: Rocks and Minerals, v. 66, no. 1, p. 56-63.
- Northrop, S. A., 1959, Minerals of New Mexico (revised edition): University of New Mexico Press, Albuquerque.
- Roberts, W. L., Campbell, T. J., and Rapp., Jr., G. R., 1990, Encyclopedia of minerals: Van Nostrand Reinhold Company, New York.
12th Annual New Mexico Mineral Symposium
November 9-10, 1991, Socorro, NM