FMF - Friends of Minerals Forum, discussion and message board

[Bob Harman]

Collectible examples marcasite on quartz or dolomite are quite uncommon in Indiana.

[Bob Harman]

Another well displayed baryte with multicolored dolomite groups on quartz

[Bob Harman]

Several more examples of calcite. Left example is on quartz, the center example is on chalcedony variety of quartz and the example on the right is on dolomite. The unifying theme with these is that the calcite crystal nearly fills the cavity of each specimen, but never-the-less are terminated with no contact points on the visible surfaces.

[Bob Harman]

Another well displayed baryte cluster with a number of well terminated blades radiating outward from the cluster's center. Similar to the previously posted example with accompanying dolomite, but this example has only a small area of minor calcite and no marcasite or smythite inclusions in the baryte crystals. Acquired in 2010.

[Bob Harman]

When I started posting all these examples, I was undecided whether to post them in the "my collection" thread as some others do or in the thread of "a mineralogical trip thru the states of the USA". It was a toss up so all the photos and descriptions wound up into this thread of Indiana minerals.

This example was collected at a small road cut in March of 2013. The road cut along Indiana route 37, North of Bloomington, is now an extinct locality as the road is currently being upgraded to Interstate 69 and the cut was leveled and contoured just within the last several months.

[Bob Harman]

For Indiana mineral collectors a nice acicular spray of millerite is one of the holy grails of field collecting. These 2 very similar, but otherwise rather ordinary quartz geodes would not be worth saving except for the fact that both had the sprays of millerite within their central cavity.
Many a collector has opened examples like these at the roadside only to have the breeze of passing traffic blow the spray out of the cavity and away.
Self collected in 2014

[Bob Harman]

Another example of ARAGONITE on QUARTZ.
For those who prefer "specimens" over the geode origin of the examples, simply gently break up the geode with a rock splitter and keep the best specimen.

[Pierre Joubert]

Bob, I really like your specimens, and to think that they were self-collected!

[Bob Harman]

Thanks PIERRE and happy New Year!,

As we all know QUARTZ (without coloring inclusions) comes in a variety of colors, from completely clear to milky white, amethyst purple, citrine yellow, smoky gray, and rose quartz pink. Several of these shades can be found in Indiana. True ROSE QUARTZ is neither found in Indiana nor commonly found as crystals most anywhere in the world. Arguably the best rose quartz crystals are from Brazil. In Indiana a peculiar shade of pink can be found; this seems to be a true crystal color, not being a shade of iron staining confined to the crystal surfaces. These examples were collected by me about 10 years ago. They are always small with a pinkish-gray lumpy outer rind. BOB

[Bob Harman]

This posting will be a bit different.

In the recent past, including earlier today, I have received several private messages from folks interested in Indiana geode collecting. I WISH TO THANK ALL THOSE TAKING AN INTEREST IN MY FINDS!

So this post will be about Midwest USA geode collecting with some special attention given to collecting in Indiana.

Midwest USA geodes are a rock structure composed of one mineral, usually quartz, often also containing nicely crystallized secondary minerals. While theoretically the geodes can be collected in a variety of localities, practically speaking there are few localities remaining open.
Geodes, in Indiana, are found in only a few quarries. Salem Quarry is now closed and flooded. Mitchell Quarry still operates, but just this week management changed and a collector friend was informed that his access to the quarry (which he has had for years) has been limited to collecting only when accompanied by a quarry employee. The collector will rethink his options. The third quarry is near the Harrodsburg road cuts and has never let anyone in to collect so geode finds are unknown. There are quarry sites elsewhere, in other states, but not many.
Geode sites are common in stream beds and farm fields, but many of these areas are on private property. Not only that, but quality finds are quite uncommon as these geodes tend to be dingy, dirty and of low quality with corroded secondary minerals; not really of interest to most experienced collectors.
Other sites include road cuts and construction sites and private lands. In order to collect quality examples at road cuts you have to have some luck, persistence with hard work, and knowledge of the specific site. Specifically, in Indiana, the southern Monroe County, Harrodsburg road cut is a good bet, but no children and don't expect high quality finds very often. Construction sites are often temporary and off limits to collecting as they are private property. Other private lands are just that; I will never give out info on any private lands as I have to have special long standing relations with the land owners to gain access.
There are no fee for collecting sites in Indiana. There are several fee for collecting sites in the Keokuk area of west-central Illinois, southeast Iowa, and northeast Missouri. These sites are my recommendations for families and casual collectors. They are safe, family friendly and quality finds are reliable.

So, practically speaking, today, in the Midwest, there are very limited sites producing truly high quality finds for most collectors. Like collecting all minerals in most parts of the world, the high end stuff tends to be found by those knowledgeable collectors and consortiums putting in money, time, and considerable effort. BOB

[Bob Harman]

One of my 2 cases at the recent 2018 Cincinnati show. The show theme for minerals was calcite and its many crystal forms.

[Bob Harman]

Two examples of Aragonite sprays on Quartz with some corroding iron oxides (limonite). Both self collected about 10 years ago.

[Bob Harman]

Two more examples of Indiana Millerite from my collection. Both were self-collected about 2007.

[Bob Harman]

One of the so called hallmarks of the rock structure called a quartz geode is that the quartz crystal tips are suppose to point inward toward the center of the cavity. While this is generally true, a very small percentage have other appearances. These are a few; all self collected.

[Bob Harman]

Two unusual examples from my collection.

The first is a 15 cm x 15 cm geode showing a double cavity layer of druzy crystalline quartz tips atop blue-gray microcrystalline quartz (chalcedony).

The second example is an 11 cm x 7 cm oval and bi-septate geode with one cavity showing blue-gray microcrystalline quartz (chalcedony), while the adjacent cavity contains druzy clear quartz crystal tips.

As I understand crystal formation as related to crystal size, the faster the crystal forms, the smaller the crystal might be. So the formation of microcrystalline quartz (chalcedony) implies rapid formation. Interesting how this bi-septate example might have formed. BOB