MIDWEST USA SEDIMENTARY TYPE GEODES

As there is a large subgroup of US mineral collectors that specialize in USA Midwest sedimentary type geodes and many more casual geode collectors out there, I am starting a new topic devoted to pix and accompanying short descriptions of these specimens, either self-collected, traded, or bought. I hope the posts will be only of this type geode.....no foreign geodes of any type and no igneous Western or Northeastern geodes and also no concretions or nodules; just Midwest geodes as from the Keokuk area, Missouri and Illinois, Indiana and Kentucky including the Hall's Gap area. If you have any nice pix and stories on this topic, please feel free to post them on this thread. These 3 examples are from my collection of Indiana geodes. Aragonite on quartz with ferroan dolomite from Monroe county, Smoky quartz on white chalcedony from Monroe county and millerite with calcite on gray-blue chalcedony from Monroe county. BOB HARMAN

Good idea, Bob. And, you got it started before my scheduled break from work on taxes!

One thing that I would like to see; whenever you have specimens that should be represented on the Mindat locality/picture data base, lets get them in there. There are a couple that you just posted that are unlike anything currently shown. In addition, locality pictures are often lacking and are just as important as the specimen pictures to folks unable to actually visit the locations. What do you think?



Geode with dolomite, baryte and quartz, SR 37, .5 miles north of Harrodsberg, (cut #18) Monroe County, Indiana. 6x5x8 cm. Circa 1965. The baryte in this geode shows signs of solution damage and crazing while the dolomite is pristine.

Cheers!

Steve

I like this topic, i will be adding to this very soon. Its all a matter of me taking some better photos.


Indiana born and raised and still living there




Byron

Three more Indiana geodes from my collection. The first is a 15 x 8 cm geode with a stout 5 x 3 x 1.1 cm color zoned barite from Monroe county, found in the 1980s. The second is a very unusual geode. It is oval, about 15 x 8 cm and shows crystalized quartz on gray-blue microcrystalline quartz (chalcedony). I have the whole geode and it is probably a geodized fossil. Self collected from Monroe county, found in 2007. The third pix is from Washington county and is a self collected geode about 12cm with 2 pristine calcites, the larger of which is about 5 cm. Hope to see others post their pix, especially of sites in other Midwest states! BOB

Are those quartz or calcite crystals on the blue chalcedony geode section? -- Very impressive geodes ! - thanks for sharing

As barite in Indiana geodes is so highly sought after, I collated several pix from other threads together onto this theme. The first pix is of a parallel group of blades with central yellow color and tips of a pale blue-white color. Click the pix to hone in on the barite group and note, near the top center of the barite, the millerite strands from the quartz thru the barite into the geode cavity. Monroe county, March 2011. The second pix is a 3.3 pristine grouping of delicate crystals. The largest is 2.5 cm and double terminated. Monroe county, about 2000. The third pix is of a 5.5 cm stout blade nestled in the "back" of the 10 cm geode. Monroe county, March 2010. Many, many Indiana geode barites have been found. The trick, of course just as with all mineral specimens, is to find large and/or pristine crystals, perfect or nearly so in every way...................... Hi Ken! hope you get some of your great specimens onto this theme. Yes, those are quartz crystals and not calcites. Click on the pix to hone in and enlarge the pix. The geode is an amazing very large variant of the dewdrop diamond variety. ENJOY, BOB

There are quite a few older geode producing areas in the Midwest that some collectors may not be aware of. I just uploaded a few pics of specimens from Missouri, one a road intersection in St Louis County, the other an old iron mine not far from Rolla. You can see them here: [www.mindat.org]
[www.mindat.org]

Kevin Conroy (2) Wrote:
-------------------------------------------------------
> There are quite a few older geode producing areas
> in the Midwest that some collectors may not be
> aware of. I just uploaded a few pics of
> specimens from Missouri, one a road intersection
> in St Louis County, the other an old iron mine not
> far from Rolla. You can see them here:
> [www.mindat.org]
> 278356.jpg
> [www.mindat.org]

Kevin, great picture and an unusual locality. In about 1965 I used to do some business with a dealer named Bill Banks; he would stop in Bloomington to peddle his specimens. I had some very nice millerite at the time but he said that he wasn't interested because he could get much better from St Louis. I never knew what he was comparing mine to. Maybe it was something like the one you referenced.

Thanks for sharing!

Cheers,

Steve

I have always liked these pseudomorphs after millerite but have never pinned down what they are exactly. Something in the jamborite-honessite realm, I suppose. The orange color is quite distinctive and does not seem to fit well for either of those two species. If anyone has information about them I would like to hear from them.

These are from the "aragonite" road cut, (old) SR37, 5.25 miles north of Bloomington, Monroe County, Indiana. Both specimens were collected in 1966.

The first is a small geode with calcite enclosing the orange mineral pseudomorph after millerite. 4x3.5x2 cm.


The second is a calcite cleavage from a geode enclosing a spray of the same orange mineral. 4x3x1.2 cm.


Cheers,

Steve



Edited 2 time(s). Last edit at 02/27/2012 08:16PM by Stephen Rose.

Hi Steve,

Thank you! There are (were) several places near St Louis that produced good millerite specimens, but not necessarily in geodes. Unfortunately now almost all of these are gone. There are a few small areas left, but they don't produce anything like they used to.

I think the best place for millerite in Missouri was the Leadwod roadcut. There were some pretty decent specimens found during construction. I looked and saw that there aren't any photos posted yet, so I just took two from my collection. The spray in the first photo is about 2.5 cm, the second is about 3 cm.



As for your yellow/orange pseudos, they may be honessite. Check out the photos here: [www.mineralatlas.com]

All the best,
Kevin

My favorite geodes are the Keokuk area geodes. They have a fantastic variety of calcite crystal habits inside them. Here are three I collected. The pagoda style clear over pink scalenohedral calcite is from Lewis County, Missouri near Canton, the iridescent pseudocubic crystal is from Brown County, Illinois and the 2 cm barrel calcite is from Hancock County, Illinois near Pontoosuc.



Edited 1 time(s). Last edit at 02/28/2012 04:31AM by Kenneth Vaisvil.

Here are two iridescent calcite geodes - my favorite types from Brown County, Illinois.

Kevin,

Great link. I found a small error. On page 9 it shows a "Martite (black iron rich sphalerite) pseudomorph after magnetite". Martite is not an iron rich sphalerite, but simply hematite pseudomorphed after magnetite.

Ironically, the photo showed on the link is the same one as the featured specimen on the martite page here on mindat, with the correct info.

Rick
I know I am in my own little world, but everyone knows me here.

Aragonite, a crystal polymorph of calcite, is occasionally found in Indiana geodes, but not nearly so commonly as calcite. The best known aragonite location is the road cut North of Bloomington in Monroe County, on Indiana route 37. This was heavily collected for many years and the subject of an article by mindat contributor Stephen Rose et. al. in Rocks and Minerals 1966 - 1967. Many other small and very localized areas of aragonite geodes occur in Monroe and neighboring Lawrence counties. These geodes are often found in heavily fossilized sandy siltstone type formations. These geodes are often accompanied by decomposing ferroan dolomite going into ankerite (old limonite terminology). The first pix is of a 12 cm geode showing sprays of aragonite and quartz coated by aragonite; it was found in July of 2011. Pictures 2 and 3 are both halves of the same 13 cm x 9 cm geode. Found in 2007, it shows sprays of aragonite on quartz. It is unusual in that no other aragonite coats the quartz crystals and virtually no ferroan dolomite is present.



Edited 1 time(s). Last edit at 03/05/2012 10:45PM by BOB HARMAN.

One of the best Millerites from any locale has to be the superb Missouri Millerite (Glenn Williams collection specimen) that was featured on the cover of the Missouri Issue of Rocks and Minerals Magazine. They don't get much better than that! a quarry in the Troy, Missouri area produced some excellent millerite altering to green honesite in calcite during the 1960's.

Calcite, along with dolomite are probably the 2 most common collectible secondary minerals found in Indiana quartz geodes. Calcite takes on many differing appearances within geodes; rhombohedral crystal forms and variations on this are more common than scalenohedral crystal forms. The first pix shows a 4 cm complex rhombohedral xtal in a 9 cm geode from 2004, Monroe county. The second pix shows a very unusual pinkish double terminated 3.1 cm rhombohedral xtal on blue chalcedony in a 8 cm geode. This appearance is similar to those crystals found in geodes from Western Illinois and Missouri. The third pix shows a complex grouping of orangish rhombohedral crystals largely filling the cavity of a 9 cm gray-blue chalcedony geode. Monroe County Indiana............ Hope others collecting Midwest geodes submit some of their specimens onto this theme for all to see. BOB

Kenneth, that Brown County pseudo cubic calcite/calcite is really unusual.

This is a millerite that I posted on another thread a couple of years ago. Weakly attached mass of radiating tufts of brassy crystals in a chalcedony geode. Hoopston, Vermilion County, Illinois. Larger 'half' is 6x6.5 cm. Circa 1960. Acquired by exchange with M. Papcum in 1967.



Cheers!

Steve

Hi Gang, going to add a few of my pieces to this thread....Note all of geodes and crystals are from Harrodsburg Indiana area. First is a geode with dolomite and calcite, what is unusual about this geode is the main calcite was broken and rehealed in place by just a small amount of calcite

Next is a couple of clacites that were loose in a volley ball sized geode that I found that had fallen around 20 feet to the road. everything was loose in this geode so I only ended up with single crystals. Calcite and baryte on the right


Loose barytes from same geode some were double term!!


Next we have a calcite that had a weird term because of a baryte blade that truncated the growth


And last, a huge sphalerite that was etched out of a solid calcite geode


enjoy!
E



Edited 2 time(s). Last edit at 03/05/2012 05:50PM by Everett Harrington.

Geodes from other states. Jacob's geode mine pieces

Calcite in a geode with marcasite or pyrite


Marcasite and/or pyrite in geode


close up photos of above



Another with marcasite/pyrite


and a few photos of sphalerites from the MO side of Keokuk




enjoy!!
E

More to come later :)