MIDWEST USA SEDIMENTARY TYPE GEODES

Several more examples of CALCITES in Indiana geodes. Rhombohedral crystals and modified rhombs are more common than scalenohedral crystal forms. The first picture shows a 3.2 cm rhombohedral crystal and 3.7 cm steep scalenohedral crystal containing MARCASITE micocrystals each in 6 cm geodes. Both are from Monroe county. Isolated steep scalenohedral forms like the one shown are quite uncommon. The second picture shows a 1.9 cm modified rhombohedral crystal in an 8 cm geode from Monroe county and a 3.3 cm group of modified rhombohedral crystals on DOLOMITE in an 8 cm geode from Washington county. CHEERS.............BOB

If all the pictures you have attached to thread posts were in our regular gallery, it would be easy to make them into a Best Minerals article about geodes from your area.

Rock Currier
Crystals not pistols.

do you swap minerals please write me at wwalljr@triad.rr.com I live in NC bill wall

There are several problems with taking really good pictures of geodes. These 3 pix of 2 display quality Indiana geodes help to make my point, even after a bit of sharpening up and lessening the shadows in photo shop. Most worldwide display geodes are "endophytic" rather than "exophytic". That is the geodes are opened hollow spheres that you have to look into and move around in a good light to see all the insides. Photos just don't show off the depth of looking into the opened geode.....endophytic. Most other minerals display well standing up and standing out just looking at them in the display case, thus they are exophytic. Then there is the lack of color in many geodes with the accompanying lack of contrast. These geodes have off white quartz with off white calcites so there is little to no contrast. White minerals are not as collectible as colorful minerals. The first pix is of an 11 cm very hi quality display geode with barites, dolomites, and a calcite. In order to fully capture this example's beauty, it has to be hand held and moved around in a good light; photos just don't capture its depth and beauty. The second and third pix are of a 15cm x 12.5cm rather large display quality specimen with yellow-orange to bright brick red dolomites surrounding multiple scalenohedral calcites containing micro marcasites. The photos just do not capture the contrast of the terminated tips of the calcite crystals. Both these geodes are from Monroe county with the larger one recently found in Dec 2011. CHEERS.........BOB

Many Indiana geodes, when opened, especially chalcedony types (microcrystalline quartz), are secondarily esthetically pleasingly colored by iron oxides. Several examples are shown here. Of course many are just dingy as well, but with diligent searching a whole collection of these colorful variants can easily be accumulated. These 4 examples are about 7cm - 8cm in size and from Monroe County. CHEERS.............BOB

Salem Quarry in Washington County, Indiana is widely known for its Celestine Geodes previously pictured on this thread. Much more common however, are thin walled quartz geodes containing off white to pale yellow calcites as pictured here. These 6 cm and 10 cm geodes were self-collected several weeks ago on our club's annual trek into the quarry. A couple of quite good celestines were also found by other field trippers. CHEERS............BOB

Chalcedony (microcrystalline quartz) geodes are very common in Indiana, but not quite as common as routine crystalline quartz geodes. Like routine quartz geodes, secondary minerals such as calcite and barite are commonly found in these chalcedony geodes. The secondary minerals found in these geodes are, however, not quite so large or showy as those found in the routine quartz geodes. Two examples of calcite are shown and two examples of barite are shown. All examples are from Monroe county and the 2 calcite examples were collected this past week. CHEERS.........BOB

True Amethyst variety of quartz is not found in Indiana, but infrequently pale vaguely amethystine colored quartz crystals are found. One such example is shown here, with a very white milky variety specimen for comparison. The amethystine specimen measures about 16 cm in greatest dimension. The milky variety measures about 19 cm and both are from Monroe County. Hope to see everyone in Denver! CHEERS...........BOB

Found yesterday at my favorite ARAGONITE locality in Southern Monroe County, Indiana. This is a 5 cm x 5 cm x 4cm quartz geode section with a spray of aragonite and scattered decaying FERROAN DOLOMITE/ANKERITE (old limonite terminology). Atop the uppermost aragonite "finger" there is a small cluster of tiny quartz crystals, making for a nice accent on this piece. CHEERS............BOB

Everett, reference to your post on March 6, (I am just catching up), I have a small geode about the size of a half dollar that is almost completely filled with the pink sponge like unknown if your are talking about the stringy crystals in the upper right hand corner of the cavity. I thought it was a Keokuk geode but it may be from Kentucky. When I cracked it open it was filled with calcite so I tossed it into some Muriatic and after a few days all that was left inside was the same stringy looking crystals. A friend of mine who used an SEM I think, said it was strontianite but I thought strontianite was soluble in Muriatic so I am not sure. I need to dig it out again and post a picture and get it tested again. Hopefully soon



Edited 1 time(s). Last edit at 08/18/2012 09:55PM by Donald Slater.

One thin seam on the Northeast Harrodsburg, Indiana road cut produces lustrous BARITE crystals that are very often strongly color zoned. The zone is always along the periphery of the crystal and ??? made up of micro MARCASITE inclusions. The first pix is of a 7.5 cm x 6 cm geode with the barite measuring 4.7 cm x 2.0 cm. The second geode is 13.cm x 10.5 cm with the barite measuring 3.5 cm. Hope to see everyone in Denver. CHEERS..........BOB



Edited 1 time(s). Last edit at 08/20/2012 01:29PM by BOB HARMAN.

Bob, your geodes continue to entertain. Your lastest find with the aragonite spray is really special (as they all are I am sure) but what really grabbed me was the part that looks like a cloud on a pedestal. I don't know how you got that out without damage. Wonderful piece.

regards,
stephanie :))

HI STEPHANIE Thanks for your kind comments. I had hoped that other Midwest geode collectors would put some of their best quality specimens on this thread, but so far not much luck. The collectors are out there and I have spoken to a few and they promise but........... Anyway, I will continue to put mine on here when I have some free time periods. Along with my pictures, I like to add comments or a short discussion as I feel this should be a learning experience rather than just seeing a pretty picture with measurements and a locality. Hope to be in Detroit in October (after Denver in a few weeks) and meet everyone. CHEERS...........BOB

I am planning on heading to Bloomington this Thursday for work, and plan to hunt geodes Friday and Saturday. Anyone got some locations for a beginner? Anyone want to tag along? I plan to go around the reservoir and then the Harrodsburg and Heltonville area unless I get a better spot from a helpful friend?

Hi All,

I went to “Wonders of the Earth”, the Scarborough Gem and Mineral Show (Toronto, Canada) this weekend and I am now the proud owner of my first Indiana Geode. There were some club members set up in the swap room there that had a some displays in the main pavilion and were selling a good number of Indiana geodes along with other things such as rainbow flint from Ohio. Thought I would share some pictures that tell the tale. All photos taken with permission.

The main geode display was provided by Roger Heaton.
A familiar poster, pictures, sample geodes and information on how to clean the geodes.



Roger’s display case. The bright display light inhibited a good photo but you get the idea.



Some of the goodies up for adoption.





Edited 2 time(s). Last edit at 09/16/2012 04:44AM by Stephanie Martin.

More goodies...

Also present were George and Joan Heaton. George is wrapping the one I selected.



This is the one I chose along with a nice paper weight chunk of polished drusy rainbow flint. Wish I had gotten more, but my time was up and had to leave. Hopefully I can meet up with them again in future, now that I’m hooked!



As I was leaving, a big birthday cake was brought in for Roger, to celebrate his 80th birthday. Happy birthday, Roger!



cheers,
Stephanie

Stephanie, Thanks for posting your pix and descriptions as the Heaton brothers are long time acquaintances of mine. I see them collecting down this way and at Midwest shows several times a year so I am glad to know they are doing well. If you looked very closely at that poster, it came from the Indiana Geological Survey and some of the specimens used on the poster were from my collection and I was given credit in the lower left corner. More pix from my collection in upcoming weeks. As I just returned from Denver and an extensive West Coast trip, I have a lot of catching up to do over the next few weeks. I will post my Denver impressions on Gail's thread. CHEERS...........BOB

Perhaps the most colorful and under appreciated and under collected of all the Indiana geodes are those from the Indiana route 56 road cuts East of the town of Salem in Washington County. These geodes can be ordinary QUARTZ geodes (often containing some DOLOMITE and small CALCITES), but most examples from higher on the highwalls show the QUARTZ to be overgrown by abundant DOLOMITE as several examples in the first pix show. Many others show CALCITE on the DOLOMITE, as shown in the next 2 pix. The geodes range from several centimeters to about 20 cm in size so quite large examples can be collected. The second example is 12.5cm x 11.5cm with a 6cm x 3cm CALCITE. The third example is 14cm x 11cm with a 4.7cm x2.5cm CALCITE. Collecting is best in winter thru early spring after freeze thaw episodes. The porous limestone absorbs much water which, after freezes, cracks and splits; sheets of this limestone containing geode halves or portions then falls and the geodes are then found along the roadside in the fallen rock. Summer collecting and using stone saws in the rock wall are both not very productive. Finding whole unbroken geodes is quite rare. The DOLOMITE colors range from pale yellow thru all shades to bright brick red with several colors often found in the same geode. This color is due to iron oxides. The CALCITES can be isolated or found in groups; isolated crystals can be up to 5+ cm in size and are modified rhombs. The best CALCITES are translucent or transparent. Looking thru transparent crystals shows the underlying DOLOMITE to be pristine pink to pale yellow, without iron oxide staining. This is similar to looking at COPPER thru the CALCITES from the Michigan copper country; the underlying COPPER is untarnished, suggesting the CALCITE in both situations formed early, prior to the rusting and tarnishing processes. SPHALERITE and BARITE are also found in these geodes as will be shown in my next grouping. CHEERS............BOB

Three more examples from my collection of Indiana route 56 road cut geodes, Washington County. The first pix shows a 14cm x 10.5cm geode containing several groupings of CALCITES to 3cm all on yellow-orange to brick-red DOLOMITE. The second pix shows a 6.5cm geode containing a 2.5cm SPHALERITE on the DOLOMITE. The SPHALERITES from this locality are reddish-black and either free standing or encased in surrounding CALCITE. This example shows several mirror bright crystal faces. The third pix shows a 10cm x 7cm geode with a 2cm CALCITE and 3.3cm x 3.3cm BARITE. BARITES from this locality are yellowish-green and often opaque and rarely terminated. CHEERS...........BOB