c/geology-rocks

Tbh, I thought vinegar was useless for cleaning rocks until last weekend

I was trying to clean some calcite I found near the river, and my usual water and brush method wasn't touching the iron stains. My kid suggested vinegar, and I figured it was a waste of time. I let a piece soak in a 50/50 mix for about 20 minutes, and the orange stains just fizzed right off. Honestly, I was shocked. I always thought you needed stronger acids for that. Now I'm wondering, what other simple household stuff works for cleaning different minerals without damaging them?

Found a weird way to clean a really dirty calcite sample from a cave in Kentucky

I had this calcite piece from Mammoth Cave that was covered in a thick, dark mud film. Soaking it in vinegar, the usual trick, just made it fizz and left a chalky mess. On a whim, I tried a 50/50 mix of water and hydrogen peroxide in a plastic tub for about two hours. The mud just lifted off in sheets without touching the crystal faces. Has anyone else found a good cleaning method for delicate minerals that won't dissolve in acid?

I spent years calling all dark, shiny rocks 'obsidian' until a park ranger in Yellowstone corrected me

I was showing off a piece of what I thought was obsidian I found near a creek, and the ranger said, 'That's not volcanic glass, that's just a really smooth piece of chert.' He pointed out the conchoidal fracture was different and it didn't have the same sharp edge. I felt pretty silly, but it made me actually learn how to tell them apart. Anyone else have a basic rock ID they were totally wrong about for way too long?

Question about those expensive rock identification kits

I spent $75 on a fancy mineral test kit last year, but the streak plates were junk and the hardness picks broke on the first quartz sample. Is it better to just buy separate tools or are some kits actually worth the cash?

Back at the old quarry outside Flagstaff and the rock face looks totally different

They've blasted so much new material that the whole stratigraphy I remember from a decade ago is just gone. Anyone know a good spot in Arizona to see clear, undisturbed sedimentary layers now?

I bought a $300 rock saw and it almost cut my finger off

So I finally saved up for a 10-inch slab saw from a big rock shop online, thinking I'd be slicing up agates like a pro. The first cut on a chunk of Montana moss agate went fine, but then I tried to adjust the vise while it was still spinning, just a tiny bit. My glove got caught and yanked my hand right into the blade guard! I heard this awful grinding sound and jerked back so hard I fell over. The saw stopped, and my glove was shredded, but my finger was just bruised, thank goodness. The whole thing shook me up so bad I didn't touch the saw for a month. Now I have this expensive machine I'm almost scared to use. Has anyone else had a close call that made you super careful around your tools?

My uncle said to look for quartz veins near the old creek bed in Sedona

Found a killer piece of smoky quartz after an hour of searching. Anyone have tips for cleaning iron stains off quartz without damaging it?

Unpopular opinion: The Mohs scale feels outdated for modern mineral hunting.

Why do guides always skip the tricky middle hardness levels?

The creek behind my place is cutting deeper into the shale.

I swear it's eroded a foot in the last few months. Is this normal for spring runoff?

Serious question, why stop kids from touching rocks?

I watch parents yell at their kids for picking up rocks, and it makes no sense. Those rocks are tiny pieces of earth's history. My niece learned about erosion just from holding a smooth stone. Letting her explore like that beats any screen time. Hands-on beats hands-off every time.

A creek side job made me see erosion in a whole new light

I used to think erosion was just dirt slowly washing away, nothing exciting. But while putting in a fence near a stream last month, I noticed how the water had shaped the bank over time. There were clear layers in the soil and rocks, each telling a bit of history. I started reading up on it and realized how dynamic it all is. Now I point out stuff like that to my buddies on site, and it feels like a little win. It's cool to understand a piece of the land I work on every day.

Heads up: My quick hammer swing on a creek rock went wrong

I was collecting samples near Miller Creek last weekend. Saw a smooth, gray rock that looked like limestone. I gave it a light tap with my geology hammer. It burst into a bunch of razor-sharp fragments. One piece cut my glove, and I was lucky it didn't hit my eye. From now on, I'm wearing full safety gear no matter what. Even simple rocks can be tricky to ID in the field.

Construction digging next door showed a fault line in the bedrock

They were prepping the ground for a new house foundation. The dig exposed a clean fracture in the rock that runs right through the property. How do you all record these temporary geology sights before they get buried again?

Vent: The old quarry near my street is getting filled in

We found fossils there all the time when I was younger. Does anyone else miss when places like that were just for exploring?

Rock ID apps never seem to get metamorphic rocks right

I wish these apps were more accurate with schist and gneiss.

Watch out for that deceptively stable looking basalt column...

I was hiking near the old lava flows and almost took a bad step on what looked like solid rock. The surface was cracked and gave way slightly under my weight. It's not just about slipping; whole sections could shift if people aren't careful. I'm confused why it seems so stable but isn't... maybe weathering?

Found a perfect quartz cluster during a job, now I'm debating if I should keep it.

I was helping a client move near a geological site and spotted this nice quartz. Part of me wants to add it to my collection, but I know it probably should stay put. My truck is already full of other people's stuff, so what's one more rock?

Lost a PERFECT ammonite to a flash flood while fossil hunting.

Never thought mineral hardness was important until I tried the scratch test myself.

Hot take: Folks say slate is always flat, but my find says otherwise.

I found a chunk of slate that's all wavy and folded. Everyone acts like it's supposed to be even sheets, but nature isn't that tidy. It got me questioning how we label rocks too strictly.

Rock hunting after rain: why waiting a day works wonders

I noticed that visiting creek beds a day after heavy rain shows new stones. It took a while to see this pattern because I used to go too soon. Once I waited, I started finding quartz and agate that were washed down. For example, after a big storm last month, I picked up several nice pieces of petrified wood. The water moves things around and exposes fresh material. Now I check the forecast and plan my trips accordingly. This simple wait makes a huge difference in what I find.