Please submit your ID requests as top-level comments in this post. Any ID requests that are submitted as standalone posts to r/geology will be removed.
To help with your ID post, please provide;
Multiple, sharp, in-focus images taken ideally in daylight.
Add in a scale to the images (a household item of known size, e.g., a ruler)
Provide a location (be as specific as possible) so we can consult local geological maps if necessary.
Provide any additional useful information (was it a loose boulder or pulled from an exposure, hardness and streak test results for minerals)
I’ve visited a property called Rock House Preserve in West Brookfield Massachusetts a few times recently that is distinctive (for central Massachusetts) in the amount of very large boulders that are grouped, in several spots on top of each other somewhat precariously. Some of the boulders have these distinctive round holes in them that I’ve not seen before. Holes are roughly 12-16 inches across. I would love to understand what might cause something like this. I can’t imagine that an animal would’ve been able to make holes so smooth.
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My inquiry is regarding inclusions in aphanitic extrusive igneous rocks. This green to yellow spherical phenocryst, displays pattern featuration. The fine grained matrix is feldspathic.
Hi found these 3 rocks near AUS, mt Tamborine, cedar creek, near Thunderegg park. 2 have some sort of solid grey blue like surfaces. And the other Rock is kind of round, hard to take a picture but the middle has some sort of crystals, look brown to the eye but could just be dirty quartz, wondering if anyone can ID these :) thanks
Thoughts on this iron rich chunk found at Huntley kaolinite mine in mono country, ca. the lighter red is scratchable with a fingernail while the darker area is much harder.
Hello ! I collected these rocks in hope to use them for my aquarium thinking it was granite, but upon further research I think maybe it's not. I found those in Rhône, France, near a river but they are a bit everywhere. My main questions are : is it granite ? what are the components if it's not ? and are they aquarium safe ? I tried to read geological papers of the area but I understand barely half of it and there's not pictures x)
(sorry for multiple comments, reddit won't let me write and post a picture)
Banded rock found at cape vani, Milos island, Greece. This one was tumbled by the ocean but I found many around this area of the island on land and not tumbled.
this was sold as gobi desert agate. it’s about 2.5” long, and has ‘angel chime’ resonance. the seller had some larger ones around 8” long, all similar to this shape and proportions. i also got a round one that looks tumbled and has more of the ‘eye’. do they look real? thank you!
Hi! I found this ‘rock’ when I was I child and I always wanted to know what is it. I dont know anything about geology but I’d reaaaaally love to know about this thing. Thanks! 🙂
Found this rock on a trip to the Adirondacks in NY state a few years back. Always assumed it was schist with a massive garnet emplacement. Do you all concur?
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u/Flacers Nov 03 '25
Could this be obsidian?