FMF - Friends of Minerals Forum, discussion and message board

[Jamison Brizendine]

Since I went to a small college in Indiana for my geology degree, I own quite a few minerals from that state. I decided to share a recent one though…

One of the minerals on my “wishlist” was a bi-colored celestine crystal from Indiana. I own a few gray colored celestines from Salem, Indiana, but I was finally able to find a locate a nice bi-colored Indiana celestine a few weeks ago at a show.

The locality is one that Bob Harman knows well, it is from the Lehigh Portland Cement Co. Quarry in Mitchell, Lawrence County, Indiana. It is approximately 5.1 x 3 x 3.9 cm and formerly from Les Tolonen’s collection. From my understanding the quarry is now flooded.

Its not a perfect flawless specimen, but I was happy to finally find one.

[Bob Harman]

In Indiana celestine occurs in 2 localities and is unlike any found in Ohio or Michigan. As Jamison showed, it is found as blocky crystals both as floaters and attached in geodes at the Lehigh Portland Cement quarry in Mitchell, Lawrence County and in the (now closed) Hanson Quarry in Salem Indiana, Washington County. The crystals are quite colorful and very collectible, being only rarely for sale at this time. Fabulous colorful examples are often displayed at mineral shows. My example pictured here was donated to the Indiana State Museum and pictured as part of their pages in the recent Mineralogical Record supplement.

The older deeper pit at this cement quarry produced the most colorful crystals in geodes, but is now flooded. The current shallower pit produces mostly colorless floater crystals with no geodes. Nice floater gypsum var selenite crystals are also found in the current workings.

[Bob Harman]

Two examples from the, now closed, Hoosier Stone quarry, also known as Salem Quarry, Washington County. Like the previous posting these are blocky, colorful and often bicolored. Also like the others these were found as floaters or attached in their host geodes.

[Bob Harman]

While millerite (NiS) is considered one of the "holy grails" of Indiana mineral and geode collectors, its oxidation products like honnessite, jamborite, and pecorite are not nearly so well categorized or pigeon holed. By sight alone, grass green colored sprays may not automatically be called one of the oxidation products of the basic millerite mineral. In fact, as the mineral is often acicular, some mineralogists suggest that some sprays might be a mixture of the basic mineral and its oxidation products so the sprays need multiple strands to be analyzed. To compound matters, there are 2 types of presentation of millerite and the oxidation products as seen here. One type is the acicular spray as seen. The other presentation is the cobweb variant, also as seen here.

[Bob Harman]

Quartz geodes make up the vast majority of common Indiana geodes and the vast number of these are ordinary, dingy and only collected by novices and casual collectors. Finding truly hi quality examples takes some persistence and searching, much the same as a collector finding superior specimens of most other minerals. With some knowledge of the geodes and persistence, good quality examples can often be found; and with the same persistence a number of quartz varieties can be found.

Smoky quartz is one variety, coming from many worldwide localities. It can be both natural and man created (most often secondary to clear colorless quartz being irradiated). When I started finding these examples in Indiana other collectors were quite amazed. I now have about 25 examples, all from a lakeside beach in southern Monroe County. They look like similar types infrequently found in the Keokuk geode area, but had never been reported from Indiana.
One fellow collector half jokingly (only half jokingly!!) thought the dark smoky color might be associated with radiation leaking from a nuclear powered alien space craft buried 100 - 200 feet below the area where they come from! But actually the color apparently is due, not to radiation effect, but to micro petroleum inclusions in the quartz as the crystals are quite fluorescent.

[Bob Harman]

No mineralogical trip thru any of the states or other countries would be complete without several pictures of important localities. Here are a few pictures of the Harrodsburg road cuts in southern Monroe County. Indiana route 37 is now a 4 lane divided highway; in the early 1970s it was widened from a simple 2 lane road. During that construction project the site is said to have swarmed with collectors and many hi quality specimens were collected and found their way into both private collections and a number of museums.

These pictures, taken in the winter, show impressive icicles that can grow to 12' - 15'. Also note the scooped out geode bearing layers surrounded by the softer, less resistant limestone matrix and the cars for scale. Crystallized H2O.....ice....is the most prominent mineral in the photos. Along with active geode and fossil collecting, many natural rock falls occur in late winter and early spring as the limestone is quite porous absorbing lots of water which fractures during freeze/thaw episodes.

[Pierre Joubert]

Fantastic Bob!

[Bob Harman]

Other than a potential rare find in a glacial erratic, copper minerals occur as micro minerals only very sparingly in Indiana and, to my knowledge, only in geodes. The 2 minerals found are chalcopyrite and malachite. These 2 examples of malachite were found in geodes on a lake shore beach in southern Monroe County.

[Bob Harman]

There are currently 2 operating (?) underground gypsum mines in Southwest Indiana near the towns of Georgia, Huron, and Shoals in Martin and neighboring Lawrence Counties. While I have never heard of crystals coming out of these mines, nice selenite crystals and the satin spar variety of gypsum are both found in at least 1 nearby quarry.
The satin spar variety and the sheet of selenite were found as part of a thin 1" - 2.5" seam in the Georgia Quarry West of the Lawrence County town of Mitchell. The tan colored inclusions are probably bits of sand and adjacent rock to the gypsum seam.
The other selenite crystals were found in the nearby Lehigh Portland Cement quarry also near the town of Mitchell; the same quarry producing the nice celestines. These selenites are found as floaters, but probably were attached until freed from the matrix by the quarry blasts.

[Bob Harman]

Dolomite is extremely common in Indiana, occurring both in geodes and in vugs in several quarries. Probably the best known non-geode examples come from the Corydon Stone Quarry in Corydon, Harrison County. There the host matrix is more correctly called dolostone (rather than limestone) as it contains a higher % of magnesium than true limestone. The fresh dolomite from here is basically lustrous pearly pink, but can be aesthetically stained by iron oxides and become a wide variety of colors from pink thru orange to brick red. The dolomite can occur alone or covered by calcites of variable sizes and crystal forms. Infrequent purple fluorite also occurs on the dolomite. There are no true geodes in this quarry, but the druzy dolomite crystals might be found lining vugs up to 3 feet across.

[Bob Harman]

More examples of dolomite from different Indiana localities. These examples are from Indiana geodes. You can see the wide range of colors and hues....pink thru all shades of orange to brick red. This seems due to iron oxides and several color shades often occur side by side in the same geode. Careful observation reveals subtle differences in the dolomite crystal sizes. The example shown above from Corydon Quarry shows much larger pink dolomite rhombs than the geode examples and the Harrodsburg examples are often slightly larger than those dolomite crystals found in examples from the Washington County road cut locality.

[Bob Harman]

Back in the 1960s (maybe even earlier) thru the early 1970s the Meshberger Stone Quarry near Columbus, Indiana (actually nearer the small town of Elizabethtown, Indiana) produced many large and very hi quality calcites. I have personally seen 15 cm perfectly doubly terminated crystals. But nothing has come out of that quarry since before 1980. The management of this quarry is the epitome of bad relations between quarry management and the collector community. I am told by very good sources that even inspectors must stay in their vehicles when doing their various inspections and duties in the quarry! My 10 cm example was collected about 1967.

[Bob Harman]

Here are several pix of another Indiana collecting locality. The rocky banks of a southern Indiana lake. The limestone at this site might be more correctly be called a sandy siltstone. The geodes at and near this site include many with aragonite and my smoky quartz examples. These pix are from the spring of 2012. The only time hiking on the lake is successful is after long dry spells when the water level is low. After rainy spells, mostly in the spring, the lake levels are high and there are no beaches as the water goes back into the wooded areas. Right now, in May of 2016, the water level on area lakes is still quite high but beginning to fall.

[Bob Harman]

As I mentioned above with my Corydon Crushed Stone Quarry dolomite examples, fluorite is often found in small crystals in that quarry. Here are the most usual expressions of that mineral. There are rare yellow cubes up to about 1 cm upon pink dolomite as seen on the right side specimen. Then there are somewhat more common purple cubes associated with the pink dolomite and also calcite. These can also be up to about 1 cm in size.
The most interesting expression tho is seen on the left side example. Congruous tiny 1mm cubes fill small voids in the host dolostone. Upon casual looks, the areas appear as ink well like depressions filled with old time dark purple fountain pen ink. Sometimes many of these occur in a localized area of the host rock making for a rather aesthetic overall appearance.

These examples were collected about 2000.

[Bob Harman]

The Indiana rte 56 roadcuts in Washington County, East of the town of Salem Indiana host some of the most colorful, highest quality, and most collectible geodes in Indiana. Many can have their best areas culled out from the geodes, making nice quality non-geode specimens.
The host matrix is very porous dolostone absorbing large amounts of water and then splitting and fracturing very readily in freeze/thaw episodes. In late winter and spring rockfalls are common and can be dangerous to careless collectors. Unfortunately many very hi quality specimens are lost to breakage as the rock wall splits, fractures and falls into many pieces before the examples are freed up and collected. My locality pix show the roadcut in winter and summer including a large hi quality geode containing large calcites on bright red dolomite. Unfortunately, it is fracturing. This pix was from 2012; the geode is now history.

[Bob Harman]

As previously mentioned, pyrite is found in many Indiana localities. Shown here are 2 varieties from a little known locality, the Georgia Quarry, West of the town of Mitchell in Lawrence County. This is the same quarry that the selenite and satin spar varieties of gypsum was pictured.
The pyrite here occurs as striated silvery cubes up to 1 cm. Occasionally many cubes can be found in close proximity in the limestone matrix which can easily be etched away with vinegar or dilute hydrochloric acid. The pyrite also replaces invertebrate fossils, a shell as shown here.

[Bob Harman]

Many dedicated field collectors, over a long period of time, find very small and localized localities. These localities produce a few specimens and then are often played out. Only 1 or a very few collectors own specimens from these finds. So it has been with me.
The 2 pix show 2 of about 10 total examples from such a locality. In about 2007, during the building of a new housing subdivision South of the city of Bloomington, heavy equipment got into geode bearing limestone while excavating a small 1 acre storm water retention pond. This was relayed to me and over the weekend I walked back and forth thru the broken up rock, finding about 10 collectible examples. One I gave to a collector friend, one I, regretfully, sold and the remainder are still in my collection. After that weekend, the site was contoured and covered over with gravel. Today it is an extinct locality under a housing subdivision and small storm water pond. Ten total specimens owned by 3 people.

[Bob Harman]

Perhaps these 2 maps should have been added to this thread at the very beginning. The map of the USA shows many of the geode locations where collector quality examples can be found. I do not profess that it is nearly complete or totally accurate, but it does give a sense of orientation when asking about field collecting geodes from the USA. Most importantly, it shows the large area of Midwest sedimentary geode locations. The Keokuk geode area in Southeast Iowa and nearby. The Eastern Missouri and Illinois areas and my Indiana area from South-central Indiana southward thru Central Kentucky into a few areas of Tennessee.

The Indiana map hi lights the area of the South-Central part of the state where mid Missippian age rock comes to and near the surface with its geode producing layers. This area is within the red line and only comprises several counties.

[Bob Harman]

There are several close but distinctly different Baryte producing localities in southern Monroe County Indiana. By far the most well known is the Harrodsburg roadcuts locality, but just a mile or two away are the Monroe Reservoir spillway locality and the virtually unknown Mission Valley Ravine locality. These 2 geodes are from the Mission Valley locality. This site has produced a few large, stout and often hi quality Baryte crystals as seen here. Fresh and well displayed examples are sought after by many mineral dealers familiar with Midwest minerals and geodes.

[Bob Harman]

Hunting for nice quality collectible quartz geodes in Indiana is a favorite family pastime and, perhaps the most important aspect of American Midwest geodes, is that it is a common gateway for many youngsters into the world of fossil and mineral collecting and geology in general.
Microcrystalline quartz (chalcedony) geodes are common, but not nearly so common as ordinary quartz geodes. Many botryoidal forms may be found including many aesthetically stained with iron oxides. As many are found already broken and open as are found as whole geodes. All these examples are from Monroe County Indiana.