Middle Tennessee Rockhounds

10/11/2026

Diagram of an underground mine showing workings and the names for these workings. Have you even been inside an underground mine? I have worked as an employee in several of them. There certainly are potential dangers of working in an underground mine. Working in the old underground mines of the 1800s was dangerous and was all done by candle light. Falls and injuries were common, and life was tough for the early day miners. The old miners sometimes missed things and put good ores out on the dumps accidentally. That is why the old mine dumps can be good places to search with a metal detector. The truth is that there is still good gold out there for prospectors to discover. Prospectors are finding great gold with metal detectors because no old time miner ever had anything like it. Have you ever found gold with a metal detector? Do have an interest in getting started? It is not easy and there is a skill to it. Let me know. I did a video on finding your first nugget with a metal detector - to learn more, watch this video: https://youtu.be/F8XZhOAvxfY

09/28/2026

09/24/2026

🌍 Earth is made of several major layers, each with different compositions, temperatures, pressures, and physical properties. From the surface toward the center, these layers include the crust, mantle, outer core, and inner core.

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🪨 The crust is Earth’s thin, solid outer layer. It averages roughly 3–19 miles thick, with oceanic crust generally thinner than continental crust.

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🔥 Below the crust lies the mantle, extending to about 1,802 miles deep. It is divided into the upper mantle, transition zone, and lower mantle. Although mostly solid, mantle rock can slowly flow over geological timescales.

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🌡️ The outer core extends from about 1,802 to 3,200 miles beneath the surface. It is composed mainly of liquid iron and nickel, and its movement generates Earth’s magnetic field.

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🧲 At the center is the inner core, extending from about 3,200 miles to Earth’s center at roughly 3,960 miles. Despite the extreme temperatures, the immense pressure keeps the inner core predominantly solid.

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☁️ Above the solid Earth is the atmosphere, a layer of gases held by gravity. Most of its mass is concentrated close to the surface, while the atmosphere gradually becomes thinner with altitude rather than ending at a precise height.

09/18/2026

Check out Tennessee

After reading through the comments on the original, I went back and rebuilt this infographic with greater attention to both the state selections and the anatomy of the fossils.

This corrected edition includes all 50 states, from Wisconsin’s Calymene Trilobite and Michigan’s Mastodon to Minnesota’s Giant Beaver and New York’s Sea Scorpion, Eurypterus remipes. The additional spotlight column also recognizes major fossil groups such as Bryozoans, Crinoids, Brachiopods, Trilobites and Ammonites.

Not every state has designated an official state fossil, and several have multiple fossil symbols, state dinosaurs or fossilized state stones. In those cases, the poster features a widely recognized fossil connected to that state.

Thank you to everyone who examined the first version closely and offered constructive corrections. That kind of shared knowledge is one of the best parts of the rockhounding and fossil community.

Which fossil represents your state—and have you ever found one?



🪨 RocknLaser ⚡️

09/10/2026

The ground beneath Wisconsin holds a story billions of years in the making! 🪨

Ancient crystalline bedrock, fiery Midcontinent Rift volcanism, tropical seas, massive glaciers, and finally the Great Lakes—all existed long before us. On this timeline, our entire human story is barely a mark at the very top.

The next time you pick up a rock, remember—you may be holding a piece of history older than nearly everything you can imagine.



🪨 RocknLaser ⚡️

09/03/2026

Sequatchie Valley an informative color map design used to illustrate the over 70 mile long, five mile wide valley and some of the major highways which today cross this unique obstacle for early settlers. Early domain of various native people and former lands of the Native Cherokee Indians until 1838 when they were forced by the U.S. Government to Oklahoma. The only detailed recorded daily journal of the Cherokee crossing the valley is in the Reverend Daniel Buttrick Diary. Records indicate two travel routes crossing the valley from the departure points at Birchwood and Brainerd Mission, at Chattanooga, TN over Walden Ridge and for at least two detachments the first leaving in November 1838, of one thousand people through present day Dunlap camping on their second travel day, near Coops Creek at the base of the Cumberland Plateau in proximity of the Dunlap Coke Ovens Park on then named Hill (Turnpike) Road. Today a printed copy details the hardships and timeline of this ordeal. The original hand written words exist in the Harvard University Library. A transcribed printed copy is displayed in the members room at the Sequatchie Valley Historical Association-Dunlap Coke Ovens Museum, Dunlap, TN

08/25/2026

Celestine(Var: Barium-bearing Celestine)(Sr,Ba)SO4, Barite(Var: Strontium-bearing Barite)(BaSr)SO4; Sphalerite ZnS. Elmwood Mine,Carthage, Smith county, Tennessee,U.S.A.,7.5x5.5x4.5cm. Small white sprays of the uncommon barium Celestine on cream colored barite”snowballs”intersected with dark red-brown sphalerite. Under LW-UV the barium Celestine is bright white, the barite is red-orange and cream.

08/24/2026

This may be of some interest for some of our members.

Join us on September 12, 2026, at the Tennessee State Library & Archives in Nashville for the Current Research in Tennessee Archaeology (CRITA) conference, hosted by the Tennessee Division of Archaeology.

This free, day-long event, open to everyone, showcases the latest archaeological research happening across the state. Hear directly from archaeologists and students as they share new discoveries and insights into Tennessee’s rich and fascinating past.

Whether you’re a history buff, student, professional, or just curious, this event is for you!

View the full schedule & details at tnstateparks.info/TN-Archaeology

08/22/2026

The Cargill Salt Mine in Cleveland runs about 1,800 feet beneath Lake Erie, and the working faces extend miles out under the lakebed. Ships pass overhead. Fish swim overhead. Below all of it, machinery is chewing through a salt bed laid down 400 million years ago.

The salt came from an ancient sea called the Salina Basin that covered this region during the Silurian period and evaporated over millions of years, leaving behind deposits hundreds of feet thick. That bed runs under a huge chunk of Ohio, Michigan, New York and Ontario. Cleveland just happens to sit in a spot where it can be reached and shipped efficiently.

Mining started in the late 1950s. Workers sank a shaft from Wh***ey Island near the mouth of the Cuyahoga and went straight down through rock until they hit salt. Everything since has been horizontal.

The method is room and pillar. Crews cut out enormous chambers and leave regular columns of salt standing to hold the ceiling. The result underground is a grid of corridors and rooms with ceilings sixty feet high in places, all of it white and gray and lit only by headlamps and equipment lights. Pickup trucks and front-end loaders operate down there. They were lowered in pieces down the shaft and assembled underground, and most will never come back up.

Conditions are stable and dry. Temperature holds around 70 degrees year round regardless of what Cleveland is doing on the surface. There is no humidity because salt absorbs it. Miners describe the air as unusually clean.

Blasting brings the salt down, loaders haul it to crushers, and a conveyor system feeds it up the shaft to storage domes on the surface. From there it goes onto ships and trucks.

Almost all of it is road salt. This mine and the one operating out of Fairport Harbor supply a large share of the deicing salt used across the Great Lakes region and the Northeast. The output rises and falls with how bad the winters have been, and mild seasons back up the stockpiles.

There is no public tour. This is an active industrial operation, not an attraction.

Which means most of Cleveland drives over it every day without a thought, on roads that stay passable in January because of what came out of the ground directly underneath.