Gypsum, USA

Can you help make this a better article? What good localities have we missed? Can you supply pictures of better specimens than those we show here? Can you give us more and better information about the specimens from these localities? Can you supply better geological or historical information on these localities?


Rock,
I would be happy to provide specimen photos and text about the following locations if you would like to create the threads.

1) Marlow, Stephens County, Oklahoma
2) Salt Plains Lake, near Jet, Alfalfa County, Oklahoma
3) Salinas Paracas, Ica Department, Peru
4) Boldut Mine, Cavnic, Maramures, Romania

One of our Canadian members should be able to develop Red River Floodway, Winnipeg, Manitoba. If not I can do a little research and handle this site as well.

Karl, thanks for catching my error. The gypsum locality on Little Beaver Creek is no longer there, thus extinct, not extant.

Michael Shaw

Rock Currier
Crystals not pistols.

Bristol mine, Iron County, Michigan - crystals coating mining artifacts after mine dewatered.

Alabastine mine, Kent Co. Michigan - Crystals to 60cm diameter 120cm long.

Lechuguilla Cave New Mexico - A large variety of rare speleothems, some of which had never been seen anywhere in the world, included 20 feet (6.1 m) gypsum chandeliers, 20 feet (6.1 m) gypsum hairs and beards

Shales in Wyoming, Colorado Utah Nevada produce selenite singles and fishtail twins to 20cm

Mission mine, Pima Co. Ariz. copper and cuprite included gypsum to 4 inches

Verde Valley, Yavapai, Ariz. pseudomorphs after glauberite

Warren Dist, Cochise, Ariz. Ramshorn gypsum

Terlingua, Texas - ramshorn

Highland mine, Arkansas - pseudomorphs after halite



Edited 1 time(s). Last edit at 06/18/2009 04:50PM by David Von Bargen.

There are of course many more localities that should be included in the USA Gypsum article and whoever eventually tackles this article will have a lot of work to do, Everyone feel free to chip in here with information. A good place to start is to go through the Gypsum gallery here on mindat and look at all the pictures and then for all the ones worth noting, copy their localities and then under the localities, the links to the images that you want to use in the article. This list can easily be made in a note pad document and then easily copied and placed in one of these threads to work on.

Rock Currier
Crystals not pistols.

Great Salt Plains, Jet, Alfalfa Co., Oklahoma, USA

Gypsum crystal showing characteristic "hourglass" shape. 2.4 x 7.2 cm.
Cluster of gypsum crystals measuring 6.5 x 7 cm.
Twinned gypsum crystals, 5 x 6 cm.

On the west side of Great Salt Plains Reservoir in northwest Oklahoma, lies a flat expanse of mud approximately 3 miles wide and 7 miles long. The lake was constructed in 1941 by damming the Salt Fork of the Arkansas River. The “Salt Plains” derive their name from a thin layer of salt which covers the flats. When brine conditions are right, gypsum crystals form in the wet mud on the flats. As the crystals form, sand and clay particles are incorporated in the crystal, forming an “hourglass” shape. The reddish-brown color is due to iron oxide in the soil. Clusters, single crystals, and twins can be found. Individual crystal may reach a size of 7 inches in length and clusters have been found weighing as much as 38 pounds. Although the area is within the boundaries of the Great Salt Plains National Wildlife Refuge, collectors can dig for crystals from sunrise to sunset, April 1 to October 15.

Marlow, Stephens County, Oklahoma

Gypsum var. selenite - a large plate of crystals measuring 11 x 15 cm with individual crystals to 2.5 cm.

The banks of Little Beaver Creek, just west of Marlow in southwest Oklahoma, produced nice clusters of gypsum for many years. Local collectors referred to these specimens as ‘rabbit-ears’ selenite. The reddish-brown coloration of the crystals is due to inclusions of soil rich in iron oxide. Nice specimens were plentiful throughout the 60's and 70's, but the location is now defunct. Nowadays, specimens such as this are rarely seen on the market, and are only available from old collections. Many older specimens have incurred damage due to the soft nature of the mineral.



Edited 13 time(s). Last edit at 06/23/2009 09:56PM by Michael Shaw.

Picture and information moved to thread above.
MS



Edited 2 time(s). Last edit at 06/23/2009 07:44PM by Michael Shaw.

There are only a little over a hundred photos on the site. Hardest might be getting people to upload gypsum photos to mindat.

If you put a minimum size on the crystals to 3-4 inches, there won't be a whole lot of good localities.

Mike, again that is good stuff, but you need to use our standard form of putting images into the articles and follow the formatting protocol that has been developed. See my comments in the Gypsum, Romania thread. Somewhere there should be a good picture or two of gypsums from Jet that really show a well formed hour glass. You have to love the good specimens from there, they are really nice.

Rock Currier
Crystals not pistols.

There are some super selenites from Fargo, North Dakota that look like those of the Red River Floodway in Winnipeg, Manitoba. Basically the same formation on a southern trend. . .

Well, those should be included. We only have one sort of scruffy picture of a small gypsum from Fargo. Do you know where we can get some pictures of the good ones?

Rock Currier
Crystals not pistols.

Rock - I have several nice specimens of the Fargo material in my collection. I will see what I can do with pictures.

Bill

Bill, Those would be appreciated. When you start looking as the images in Mindat with a critical eye you realize how much they need to be improved. That is one reason I am trying to upload as many good ones as possible from my slide library.

Rock Currier
Crystals not pistols.