Septarian Concretions

- Unveiling the Marvels of Septarian Concretions!

Hey there, Rock Enthusiasts! 🌟 Get ready to explore the enchanting world of septarian concretions. They’re like a delightful box of chocolates—full of surprises! Each one is a unique treasure waiting to be discovered, and for us rockhounds, it’s often a sweet surprise inside—no kidding, LOL!

And guess what? These wonders can be found in nearly every black shale around the globe! I’ve been cracking these beauties open for a while now, so check out the ‘Backstory’ below for a little stroll down memory lane. But here’s the kicker: there are some seriously stunning fluorescent ones just a 5-minute walk from my backdoor!

Frontier Formation Septarian Concretions

Let’s talk about these gems! They’re easier to spot during the day since they’re more erosion-resistant than black shale. Often, they have a lovely brownish-tan hue thanks to their iron content, which makes them really stand out.

- Prime Septarian Concretion Country

- Many Large Septarian Concretions Weathering Out Of Shale

Now, these concretions can be quite hefty, requiring a bit more energy to crack open. Personally, I prefer using a rock hammer on the smaller, less weathered ones. Keep an eye out for those with calcite crystal-filled septa—they’re totally worth investigating!

- This Is The Kind I Look For

Finding one like this usually means there are others nearby, often less weathered and oxidized. They tend to be barely exposed, dark-colored, with septa filled with stunning calcite crystals—just like this beauty.

- Premium Septarian Concretion At Night

Fun fact: I found this one at night, snapped a picture, and returned a week later during the day to collect it. But wouldn’t you know it? I couldn’t find it again! I’ve been back several times, and still no luck. Maybe it’s destined to be someone else’s treasure.

Septarian Concretion Specimens

Now, let’s feast our eyes on some fluorescent septarian specimens! These beauties shine their brightest under long-wave ultraviolet light.

• Calcite fluoresces in shades of brown, tan, cream, and yellow.
• Barite shines yellow-white to bright white.

And get this—they’re phosphorescent too! Different generations of calcite and barite glow in white, yellow, green, and blue.

- Calcite Crystals. Pierre Shale, Western South Dakota

- Calcite, Aragonite, Barite. Frontier Formation, Central Wyoming

- Calcite, Aragonite, Barite. Frontier Formation, Central Wyoming

- Calcite, Aragonite, Barite. Frontier Formation, Central Wyoming

Backstory

Bad Business

Let’s dive into the backstory! I’ve had quite a journey with septarian concretions. My first encounter was with Pete Larson and James Honert on the Cheyenne River during my days at the South Dakota School of Mines.

Pete was familiar with the area, and together we cracked open concretions. These weren’t just any concretions—they held well-preserved fossil cores with baculites, occasional ammonites, and iridescent shells filled with brilliant calcite crystals. Magical, right? But that was just the beginning.

Years later, I teamed up with Bill Roberts, and we found a massive concretion along Elk Creek that housed translucent golden barite crystals with calcite. It was a once-in-a-lifetime find, but unfortunately, my share was far from what was promised. That experience marked my exit from a less-than-honorable business, and trust me, it was the best decision I could have made.

Fast forward to today, and septarian concretions still hold a special place in my heart. They’re not just rocks; they’re memories of thrilling adventures and the joy of discovery.

Good Direction

A decade later, I found myself back in western South Dakota, cracking concretions again—this time with my young family and friends Lloyd and Viola Garnick. Much better company, I must say!

- Calcite Crystals On An 18-Inch Pierre Shale Specimen. Western South Dakota

Today

And here we are today! I can step out my backdoor and find these beauties. Sure, the cavities and crystals are smaller, and I haven’t spotted any fossils, but they’re beautifully fluorescent, especially with my new, more powerful long-wave LED flashlight.

So, there you have it—a little trip through my septarian adventures. Some memories are linked with people and places, but what I remember most is the thrill of cracking open that first one on a scorching day. Ah, good times!

- My Young Son With His Pile Of Treasure

I still feel that same thrill today when septarian concretions remind me of those moments. And the best part? The most fluorescent ones are just minutes away.

Take care and keep on rockin’! ✨

Cheers, D 🪨🔥