Minerals are Earth’s versions of flowers. Think about it. They occur in virtually every known color (even more than flowers which never look metallic or transparent) and have varying symmetry. Just like the rose doesn’t resemble an iris or a columbine has no similarities with the pitcher plant, crystals come in a variety of forms. Crystals reflect the internal arrangement of atoms.
Minerals occur in igneous, metamorphic, and sedimentary rocks. Minerals like calcite and quartz occur in all those rock types. There are many minerals that form in specialized conditions and some that are only known from one or two localities across the planet.
Kentucky and Indiana, my back yard, is underlain by sedimentary rocks. The most common minerals are calcite, dolomite, gypsum, quartz, and pyrite. Barite, fluorite, sphalerite is locally common. There are four noteworthy areas in Kentucky where minerals are especially rich (though not diverse):
- Central Kentucky Mineral District stretching between Henry and Boyle Counties
- Western Kentucky Fluorspar District – part of the world-renowned Illniois-Kentucky Fluorspar District
- A tiny kimberlite outcrop in Elliott Co., Kentucky (is far eastern part of the commonwealth near Ashland) producing small pyrope garnets, olivine and ilmenite – no diamonds!
- Geode belt stretching in an arc from Meade to Boyle Co., KY – as well as several counties in Indiana.
I wrote numerous articles on mineral collecting and they will be posted over time. A short one is below. My bibliography can be found in under “About Alan.”
The Garza Collection
Since 2017, I have been helping Steve and Dee Garza organize, clean, label and sell minerals from Steve’s vast collection. Steve collected in New England between the mid-1960s and mid-1980s and the Ohio Valley from 1986 to 2016. He did a lot of buying and trading over 50 years diversifying his collection. Although a big chunk of the collection has been sold, thousands of minerals are still being processed from the Garza’s garage. It will take several more years to go through everything.
The list will be updated as timely as possible. However, I’m not a full-time dealer.
Based on the short article first published (without photos) in Mineral News, September 1993. Published here Jan. 16, 2022.
Malachite from Jefferson Co., Kentucky
While searching for landscape rock at the Roger’s Group (Avoca) Quarry in Middletown, Kentucky, the writer noted a number of calcite pockets in a couple boulders. The rock is the Laurel formation, a dolomitic limestone mined on the surface. Some of the calcite contained the iron-copper sulfide, chalcopyrite, as inclusions just below the crystal surfaces. Some of those are coated with a bright green malachite coating which may extend into the surrounding calcite. Although the chalcopyrite crystals are only 2 mm across, the intense color in contrast to the white calcite made it visible from more than six feet away (Figs. 1 & 2).
No additional mineralization was noted, although only a small fraction of the quarry complex was examined. This occurrence is not common in this region, with other similar (minor) occurrences at the Brownsboro Quarry (in the same formation) and the Irvington Quarry in Kentucky as well as the Corydon Quarry in Indiana.
Addendum: The surface operations ceased shortly after this article was written. The company now mines limestone 800 feet below the surface in the same Ordovician limestone deposits that are exposed at the surface in central Kentucky at the apex of the Cincinnati Arch.