r/geology

What's your dream geology project?

This amphibolite-facies micaschist features a stunning staurolite sigma porphyroclast centered on an older garnet core. The characteristic sigma geometry proves that the rate of marginal recrystallization was higher than the clast’s rotation speed during deformation. Within this two-mica pelitic system, these rigid clasts often work in tandem with the surrounding mica foliation to develop S-C planes, providing a clear kinematic indicator of the ductile shear sense during the metamorphism.

(AA battery for scale)
First photo: One Snowflake cross
60 degree cross
Second photo: possible “gem”/“facetable” specimen

I found no similar specimens on the internet,
Every last piece allows some light to pass through.
I will be cleaning these off and selling them soon.
^^^(All funding will go to Star Garnet documentary)

I could use some advice on how to grade these specimens based on (color, strength, shape, etc)

Please comment any experiences, stories, or tips!
Anything helps

(Excluding New Zealand, Australia, New Caledonia, and Papua New Guinea), many Oceanian islands formed after the major phases of continental drift. These islands are mainly volcanic islands or coral atolls, including Hawaii, Kiribati, French Polynesia, the Cook Islands, Samoa, American Samoa, Tokelau, Niue, Nauru, the Marshall Islands, the Federated States of Micronesia, Wallis and Futuna, Tonga, Vanuatu, the Northern Mariana Islands, Palau, Fiji, and Pitcairn.

Past: Similar volcanic islands may also have existed in different parts of the world during the Pangaea era. What happened to them over geological time? Were they destroyed by tectonic activity and continental drift, submerged beneath the ocean, or transformed into other geological structures?

Future: What could happen to these modern Oceanian islands over the next hundred million years, assuming they are not submerged earlier by rising sea levels? Since they are not continental fragments, will they eventually erode away, sink beneath the ocean, and merge into tectonic boundaries?

Hello, I have no idea about geology what so ever but I am currently at the northern coast of Sicily and saw those very cool looking sediment and rock layers. Can anyone tell me something about how they are formed or about the geology of Sicily?

saw this on a rock in a lake in the adirondacks. any idea what may cause this?

I just found a really interesting article which talks about a fairly recent scientific discovery and Baltimore sits right on top of it! It's called the Piedmont Resistor and it's basically a huge chunk of Pangaea.

When the supercontinent of Pangaea started to tear apart along what is now the east coast, magma flooded up through the crust and buried over a thousand mile strip of land under a 100 mile thick slab of volcanic rock. Some ended up under the newly forming Atlantic ocean, but apparently we're sitting on a large slab of that 200 million year old chunk of a lost continent!

Yeah, maybe it's not the Ravens, but it's pretty cool!

https://www.abovethenormnews.com/2026/05/15/lost-continent-buried-beneath-united-states/

There's a little more technical article here:

https://www.science.org/content/article/deep-earth-map-reveals-lost-u-s-continent

Very heavy, that’s what peaked the interest but after googling a bit I’m curious?

My best attempt at zooming in from Macro to Micro.

Chimney mtn, Adirondacks

On the morning of May 18, 1980, I was fishing in a bass tournament on Silver Lake in Cowlitz County, Washington. These photos were taken by a fellow bass club member (I’m sorry I no longer know his name) and show my dad and me fishing about 30 minutes before the eruption of Mount St. Helens, and then of the ash cloud.

We were idling through the lily pads on our way back to the resort when we saw the initial eruption begin. We never heard a thing. Maybe the boat motor masked it, or maybe some strange acoustic effect carried the sound elsewhere.

When we reached the resort, it was total chaos. People were running around like the world was ending, loading campers, pulling boats out of the water, and trying to leave.

We heard the I-5 bridge over the Toutle River had been closed, so my dad figured we weren't going anywhere for a while. My cousin, my dad, and I motored over to a small store by the lake, bought some beer, then sat in the boat out in the middle of the lake watching the eruption unfold.

The ash cloud spread above us but never reached our area since most of it traveled east. The cloud blocked the morning sun, the temperature dropped, and lightning flashed inside the ash plume.

Eventually, we returned to the resort and learned the interstate had reopened. We packed up the boat and camper and headed home.

It was a once-in-a-lifetime experience. We went there hoping to maybe see a little steam rise from the mountain. Instead, we witnessed history.

Do you have a Mt St Helens story?

Mammoth Hot Springs - Yellowstone National Park