c/geology-rocks

Was hiking near Sedona and noticed the red sandstone layers are way more tilted than I expected, like almost 45 degrees in some spots.

I was on the Bell Rock trail and kept looking at the cliff faces. It really hit me how those layers got pushed up that steep. Makes you think about the forces that were happening there, you know? Anyone know a good spot in Arizona to see even more extreme folding?

My trusty Estwing rock hammer handle split clean in two after 15 years of service during a mapping trip near Moab.

I had to wrap the head with a ton of duct tape and a bandana just to finish the day's work, so what's a good, tough replacement that can handle a lot of desert sun without getting brittle?

Tbh I used to think a rock was just a rock until my kid's 3rd grade science fair project last month.

Just realized how much I learned from that old guy at the Ruby Falls gift shop.

He picked up a piece of flowstone, handed it to me, and said, 'This isn't just a rock, kid, it's a record of every drip of water for the last ten thousand years,' and I've never looked at formations the same way since, so what's the one thing someone told you that totally changed how you see rocks?

Vent: I finally understood what 'metamorphic' meant after staring at my kitchen counter for three years

I mean, I was just wiping down the granite this morning and it hit me that the swirls weren't painted on, they were literally squished and baked into the stone under a mountain a billion years ago, which is kinda wild when you think about it, right?

Back at the old quarry near my hometown and the change is wild

They've cleared so much of the face, you can see the full shale and sandstone layers now. It made me think about how many fossils we just walked over as kids without knowing. Anyone else have a spot that looks totally different now?

My stubborn calcite vein took 3 whole days to map right because I kept mixing it up with the quartz next to it.

I had to re-check my field notes from the Arizona site and use a fresh bottle of acid to finally be sure, so has anyone else had a simple ID turn into a huge time sink?

TIL my old rock hammer was slowing me down compared to a proper geologist's pick. The pick's pointed tip is way better for splitting shale.

My $80 rock hammer purchase was a total game changer

I used to just use a regular hammer and a chisel for splitting shale in my backyard near the river, but it was messy and I broke a lot of good pieces. I finally bought a proper Estwing rock hammer last fall, and the difference is night and day. The pick end is perfect for prying layers apart cleanly. Has anyone else had a tool that completely changed how you collect samples?

Picking granite over quartz for my kitchen counter was a real rock moment

Went with the granite slab from the local yard, not the man-made quartz. It has these tiny flecks of mica that catch the light just right. Anyone else get stuck on natural stone versus engineered stuff?

I think the obsession with perfect quartz crystals is missing the point

Last year at the Tucson Gem Show, I saw a guy pass over a stunning, complex piece of smoky quartz with amazing phantoms because it had a small chip on one termination. In my experience, the flaws and breaks often tell the real story of formation and pressure, way more than a sterile museum piece. Has anyone else found a 'damaged' specimen that taught them something cool?

Got into a real argument about the Chicxulub crater at a field camp in Arizona

We were mapping near the Kaibab Formation and my friend Mike insisted the impact winter was the main dinosaur killer, but I think the Deccan Traps volcanism did more damage over time. He pointed to the global iridium layer, I brought up the longer climate shifts from the lava flows. Anyone have a strong take on which event was actually worse for life back then?

Took my niece's rock tumbler for a spin against my old hand-polishing method

My 8-year-old niece got a National Geographic hobby tumbler for her birthday, so we decided to test it against my old-school way of polishing agates with a Dremel and cerium oxide paste. After one week in the tumbler, her Lake Superior agates looked way better than the ones I spent 3 hours on. The tumbler gave them a deep, even shine, while my hand-polished ones still had flat spots and scratches. I guess the constant, gentle tumbling action just works better than me trying to hold a tiny rock steady. Anyone have a favorite grit sequence for getting that final glass-like finish on quartz?

Rant: A simple granite slab identification turned into a three day puzzle

A client in Phoenix wanted to know if their kitchen counter was 'real' granite or a lookalike. I told them to do the scratch test with a key, expecting a quick answer. The key left a mark, which should mean it's softer than quartz, but then the acid test didn't react at all. I spent the next two days digging through old geology texts and calling a buddy who works in a quarry before we figured out it was a specific, dense gneiss that polishes up like granite but has different properties. Has anyone else had a common test totally backfire on them?

My professor told me to always check the local bedrock before digging a pond

He said, 'The map says sandstone, but go look at the creek bank first,' and I'm so glad I did. I was planning a small pond on my property near Lexington, Kentucky, and a quick walk showed fractured limestone everywhere, not solid sandstone. That would have leaked like a sieve. Anyone else have a story about a geology tip that saved a project?

Back in the day, I'd just use a cheap rock hammer from the hardware store for everything

Dropped about $75 on a proper Estwing geological pick a few years back, and it's the only tool that hasn't chipped on me when prying out stubborn concretions. Anyone have a good alternative for cleaning matrix off delicate specimens without damaging them?

My uncle swore by using a vinegar soak for cleaning calcite off a fossil I dug up near Cincinnati, and after a week of watching it fizz, the detail was incredible.

Has anyone else had luck with mild acids on different minerals, or is it a quick way to ruin a good find?

Serious question, is a rock hammer always the right tool for the job?

For years, I only used my Estwing rock hammer for every field sample, even on soft shale. Last fall in the Badlands, I watched a colleague use a simple masonry chisel and a small sledge to pop off perfect, thin layers. I tried it on a stubborn concretion and got a much cleaner break. Now I carry both, but I wonder if I was just stuck in my ways. What's your go-to tool for delicate sedimentary work?

I know everyone loves the new visitor center at the Grand Canyon, but I think the old displays were way better for showing the actual rock layers.

Serious question, did anyone else learn the Mohs scale wrong?

I was trying to identify a piece of quartzite from a hike near Sedona and my scratch test was way off. Turns out I'd been using a steel nail thinking it was a 5.5, but my old field nail is actually closer to a 4. I've been mislabeling specimens for years. How do you guys keep your hardness picks accurate?

My neighbor's kid asked if all the rocks in our yard came from a volcano, and it made me realize how many people think geology is just about lava.

I explained that our local gravel is mostly sedimentary, formed from an ancient riverbed over millions of years, and his mind was totally blown.

Question about a weird rock I found near the old quarry in Springfield

I was out walking my dog near the old limestone quarry in Springfield last weekend. My dog started digging at the base of a big pile of tailings and uncovered this rock that looked like it had little green crystals all through it. At first I thought it was just some slag or something, but when I got it home and washed it off, the crystals were really clear. I took a picture and showed it to my friend who works at the community college. He said it looked like olivine in basalt, which is weird because that quarry is all sedimentary rock. He thinks maybe a glacier dropped it there during the last ice age, like 10,000 years ago. I never really thought about how rocks can travel so far from where they formed. It makes me look at every loose rock in a field differently now. Has anyone else found a rock that just didn't belong where it was?

Looking back on my first real rock saw choice

About five years ago, I had to pick between a cheap tile saw from a hardware store or saving up for a proper lapidary saw. I went with the tile saw because it was only $120 and I was just starting out. It worked okay for soft stuff like shale, but the first time I tried a piece of agate from a trip to Oregon, the blade chipped and ruined the slab. I ended up buying the better saw a year later anyway, and it's still running strong. Anyone else have a story about a tool they cheaped out on and regretted?

My $75 rock hammer purchase was the best and worst decision I ever made for my collection

It let me properly split a gorgeous piece of agate I found near Sedona, but now I can't walk past an interesting-looking rock without sizing it up for a crack, which is becoming a problem.

I finally understood why my rock ID was always off

Honestly, I was trying to identify this greenish rock from a creek bed near Flagstaff for months, calling it serpentine. Tbh, a geology student at a club meeting last Tuesday just picked it up, licked it, and said 'This is chlorite schist, you can tell by the cleavage and the way it sticks to your tongue a bit.' Ngl, I felt pretty dumb for missing the foliation. Has anyone else had a simple trick totally change how you see a common mineral?