This area of the web site is dedicated to showing minerals from the local geographic area that surrounds where most KYANA members live and collect.

What Is a Mineral?

Minerals have four defining characteristics:

• Naturally occurring
• Inorganic
• Specific crystalline structure
• Specific chemical composition

Cubic zirconia is man-made and is not a mineral. Neither are synthetic gemstones or aluminum foil. Coal and pearls are created by organic processes. Opal does not have a crystalline structure. Amber does not have a specific chemical composition (and is also organic).

Petrified wood can be a mineral (quartz) when the organic component has been completely replaced by silicon dioxide through natural processes. Some minerals may grow in something that is analogous to plant-like structures (gypsum flowers and barite roses), but there is no organic component.

Minerals result from atoms joining through electrical bonds to produce a definite internal structure. Salt (the mineral halite) is a combination of sodium and chlorine atoms in a specific arrangement. These combinations of atoms, when expressed to their end result, can create crystals.

The Occurrence of Minerals in the Ohio Valley Region

Minerals in our region occur commonly in two types of deposits—geodes and vugs. In central and western Kentucky and southern Illinois they also occur in veins. Joint fractures (natural stress fractures with thin gaps) are a minor source of minerals because they have little space for free crystal growth. The counties listed below are not a complete list – think of them as a “sampler.”

Geodes are roundish rocks lined with quartz ranging from about ½ inch to more than 2 feet across. Some are “exploded” fossils, but most are from gypsum nodules that have been re-mineralized. They most commonly occur in shale, siltstone and limestone, particularly in Mississippian-age rocks. Geodes are common, although not every one is hollow and crystal-lined. In Kentucky, they are especially well known in Boyle, Bullitt, Green, Hardin, Lincoln, Meade, and Pulaski Counties. In Indiana, they are known from Lawrence, Monroe and Washington Counties. The best minerals occur in road cuts or quarries, but exposures in streams will have numerous quartz and chalcedony geodes.

Vugs are irregular to round openings in rock lined with crystals, without a quartz lining. They range from an inch to six or more feet across. Also called pockets, these occur in limestone or inside fossil corals and stromatoporoid sponges. Calcite and dolomite are the most common minerals in vugs. Vugs are more widespread than geodes, but require fresh exposures to have collectible crystals. In Kentucky, notable locations for vugs include Bath, Breckinridge, Hardin, Jefferson, Nelson, Oldham, Pulaski, Taylor and Washington Counties. In Indiana, they are documented from Allen, Bartholomew, Franklin, Harrison, Jennings, Marion, Pulaski, and Shelby Counties. Vugs with world-class crystals are also associated with bedding replacement deposits in the Illinois–Kentucky fluorspar district (see under “veins” below).

Veins are vertical to near-vertical mineralized zones. They can be thinner than one inch or as wide as fifty feet. Veins can be solid, but mineral collectors love those with gaps allowing crystals to grow. They are usually associated with “mineral districts” – multi-county areas with the widespread injection of minerals from deep within the crust. In our region, minerals were deposited at low temperatures (below 150°F). Veins are noteworthy in central Kentucky from Anderson, Boyle, Owen, Scott, Fayette, and Woodford Counties. In the Illinois–Kentucky fluorspar district veins are known from Crittenden and Livingston Counties (Kentucky) as well as Hardin and Pope Counties (Illinois). The largest crystals in Kentucky are associated with veins in Boyle and Fayette Counties – they have been documented in excess of 200 pounds!

Igneous deposits are found in Elliott County (far eastern Kentucky) and Crittenden and Livingston Counties in far western Kentucky (and in adjacent southern Illinois). Neither of these curious rocks has collectible minerals. Both are rare ultramafic (magnesium-iron-rich) deposits derived from the Earth’s mantle. Elliott County’s is a kimberlite, erupted from 120 miles below. In some locations these rocks contain diamonds, but not here. The western Kentucky deposits are thin veins called alnöites. These are finely crystalline dark greenish-gray rocks. While they could also have diamonds, none have been found.

We encourage you to explore other resources to learn the physical properties used to identify minerals. This web page focuses on images of minerals found in the area. Since the Ohio Valley is covered by sedimentary rock, the number of mineral species is not very large. More minerals are tied to igneous and metamorphic rocks. There are individual mines that have more mineral species than are found in all of the states bordering the Ohio River!

The “top five” most abundant minerals in our region are: calcite, quartz, pyrite, dolomite, and fluorite.

Mineral Examples & Localities

Click the locality links to view specimen photos on Mindat.org.

Anatase (Titanium Dioxide – TiO₂)
Halls Gap, Lincoln Co., KY

Barite (Barium Sulfate – BaSO₄)
Danville, Boyle Co., KY
East Faircloth mine, Woodford Co., KY (with fluorite)
East Faircloth mine, Woodford Co., KY (with fluorite)
Halls Gap, Lincoln Co., KY
Harrodsburg, Monroe Co., IN
Harrodsburg, Monroe Co., IN
Owingsville, Bath Co., KY
Georgetown, Scott Co., KY
Springfield, Washington Co., KY
Barite on calcite, Springfield, Washington Co., KY

Calcite (Calcium Carbonate – CaCO₃)
Corydon, Harrison Co., IN
Corydon, Harrison Co., IN
Danville, Boyle Co., KY
East Faircloth mine, Woodford Co., KY
East Faircloth mine, Woodford Co., KY (with fluorite & barite)
East Faircloth mine, Woodford Co., KY (with malachite & chalcopyrite inclusions)
Halls Gap, Lincoln Co., KY
Halls Gap, Lincoln Co., KY
Harrodsburg, Monroe Co., IN
Harrodsburg, Monroe Co., IN
Hutson Mine, Livingston Co., KY
Georgetown, Scott Co., KY
Irvington, Breckinridge Co., KY
Owingsville, Bath Co., KY
Springfield, Washington Co., KY

Celestine (Strontium Sulfate – SrSO₄)
Highway 1638, Meade Co., KY
Highway 1638, Meade Co., KY
Highway 1638, Meade Co., KY
Highway 1638, Meade Co., KY
Kings Mountain, Lincoln Co., KY (with lavender quartz)

Cerussite – PbCO₃
Columbia Mine, Crittenden Co., KY
Columbia Mine, Crittenden Co., KY
Halls Gap, Lincoln Co., KY
Hickory Cane Mine, Crittenden Co., KY
Hickory Cane Mine, Crittenden Co., KY
Hickory Cane Mine, Crittenden Co., KY