Skip Navigation

January-February 2016

Print
Email
ResizeResize Text: Original Large XLarge

Letters

ARIZONA STATE METAL

The article on “State Earth Science Symbols of the American Southwest” by Mark Jacobson (July/August 2015, pages 306–313) included turquoise as the state gemstone and petrified wood of the evergreen species Araucarioxylon arizonicum as the state fossil.

To those can now be added copper as the state metal. Arizona's nickname is “the Copper State,” as Arizona's mines produce about 65 percent of U.S. copper production. So it seems fitting that the state metal should be copper. The official designation came about when students at Copper Creek Elementary School in Oro Valley, Arizona, initiated a campaign on 6 February 2015 to make copper the official state metal of Arizona. With strong lobbying support from the mineral and mining community and a bipartisan coalition of legislators, the Arizona Senate introduced and passed Bill 1441 soon after learning of the students' civic project. On 27 March 2015, Gov. Doug Ducey signed into law the measure that established copper as Arizona's official state metal.

Efforts are currently underway by several of us in Arizona's mineral collecting community to have the legislature designate wulfenite as the state mineral.

INTERESTING QUARTZ

Two odd quartz specimens from Mount Malosa, Zonba district, Malawi. Left: 8 × 3.5 × 3.6 cm; right: 9.2 × 4 × 4 cm.

I published a column in the September/October 2012 issue (pages 459–462) titled “Not Japan-Law Twinning” in which I described odd quartzes from the Erongo Mountains, Namibia. Although these appear to be the product of multiple Japan-law twinning, they are instead an example of epitaxy in which the orientation of the quartz crystals has been dictated by their having grown on large feldspar crystals, the latter having been eroded away. At the time I thought this phenomenon was probably unique to that locality, but now Fabre Minerals has offered on its web-sales site a half-dozen very similar examples from Mount Malosa, Zomba district, Malawi, two of which are illustrated here.

Quartz (smoky quartz), 5 cm tall. Sceptre claims, Emerald Lake, Mayo mining district, Yukon Territory, Canada. Private collection.

In addition, I have just received from Mark Mauthner a photo of a probable example of this phenomenon from the Sceptre claims, Emerald Lake, Mayo mining district, Yukon Territory, Canada. So perhaps such quartzes are not so rare after all.

CELESTINE GEODES

Two Celestine-quartz-calcite geodes from Makhtesh Ramon, Israel.

I was delighted to read the article “Celestine-Bearing Geodes from Wayne and Emery Counties, Southeastern Utah: Genesis and Mineralogy” by Daniel Kile and others in the May/June 2015 issue (pages 314–334). I have a special place in my heart for celestine geodes: Together with several colleagues, I spent two years studying such geodes. Remarkable celestine-quartz-calcite geodes occur in the Makthesh Ramon area of the Negev Desert in southern Israel, and while researching the literature about possible formation processes, we could not find anything similar at all. Imagine my surprise when I saw the photographs in the article that in some cases look nearly identical to our geodes! Furthermore, our “unique” process of celestine mineralization after sabkha-derived anhydrite dissolution shares many characteristics with the formation process described in the Rocks & Minerals article. This does indeed feel like finding my (geological) twin, halfway across the planet! I would like to thank the authors for bringing a smile to my face and Rocks & Minerals for publishing the article.

Here is the citation for our study, which also includes wonderful images:

Anenburg, M., O. M. Bialik, Y. Vapnik, H. J. Chapman, G. Antler, Y. Katzir, and M. J. Bickle. 2014. The origin of celestine-quartz-calcite geodes associated with a basaltic dyke, Makhtesh Ramon, Israel. Geological Magazine 151:798–815.

I also included two unpublished pictures of said geodes so readers can enjoy their beauty.

In this Issue

Taylor & Francis Group

© 2017 Taylor & Francis Group · 530 Walnut Street, Suite 850, Philadelphia, PA · 19106