Science Friday, the geode edition, as requested by Zod (1/3): Geodes form, with very few exceptions, almost exclusively in sedimentary rock.
The first thing I think of when I think of geodes is volcanoes, which means igneous rock. I knew this had to be false.
Metamorphic rocks as well
Wait, igneous rocks. Yeah. Right? Geology class was a long time ago lol
Usually igneous or sedimentary, though metamorphic can be possible.
I'd say no, it's volcanic rock. It needs great pressure and heat to form them.
Actually, they form closer to a process like rock candy.
It's true. It actually is a lot like making rock candy.
Geodes (in case you're wondering, they're the rocks that look like plain rocks on the outside, but have shiny crystals on the inside) form in both sedimentary (rocks formed from particles deposited by water or air) and
igneous (rocks formed from lava) rock. While it's possible for geodes to form in certain metamorphic rocks (rocks made from other rocks due to heat/pressure/etc.), crystals formed within metamorphic rocks tend to be quite small.
here are some geodes:
I object. Do they form in sediment and lava equally? Or do they form in sediment more often? 😏
Both are pottery conducive to it, as all they really need is porous rock with a cavity. Since sedimentary rock is more common, I imagine more geodes are sedimentary geodes.
Yes, I'm being a dork.
My objection stems from syntax of your question. It's essentially asking which is more common. I guessed sedimentary.
I thought I had distinguished it well enough. But it was 3am, so I thought a lot of things.
I had a small pile of geodes in my back yard creek. So at one point my creek was hot and pressurized?
Could be. That, or there were small animals/nests/etc. encased in stone, which, if the stream has been there long enough, is totally possible.