r/askgeology

Found this while digging a hole in my yard in the Sugar House area of Salt Lake City. It was about 3 feet underground, and I remember going through dirt and a pretty distinct clay layer while digging.
It was originally packed/covered with dirt and clay. After soaking it in water and gently brushing it, I uncovered a ton of small crystals and crystal-lined cavities. The part I can’t figure out is the really straight, angular, almost geometric-looking structure running throughout it.
The photo with the measuring tape is from before I cleaned it. The close-ups are after soaking/cleaning, although there’s still some clay down inside the cavities.
Any idea what this is, what the crystals might be, or what would cause it to form like this?

I apologize some of the macro attempts are blurry, the minerals are interesting.

I found this sitting in the dirt beside the sidewalk here in Thunder Bay, Ontario. It had an odd shape and felt oddly heavy so I thought I would cut it. It was nicely encased in clay and iron oxide.

There is a picture from the original cut before I polished it included.

It is not magnetic, scratching with a nail is all over the place in hardness, even among areas that look the same. The colour is amazingly black depending on the angle the light hits it.

I have not seen any rock around here quite like this in my time cutting and polishing them. Some form of diabase, or gabbro, or diorite is all the guesses so far.

Thanks for any help.

Source video link: here
Source video comment:

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Would there be any continents at all, or would most land be below water? I'm imagining that the primordial volcanism and convection could be enough to make some elevation differences. Maybe those early continents would be more blobby and smooth since they're not formed by plates moving?

My thought process right now:

I used Orogen to initialize some plates, but the theoretical continents are harder since modern landmasses "hug" their plates due to being formed by them and certain rules apply, while ancient ones pre-date plate tectonics. But also since plates form based on weak points in the crust, continents will still follow some rules wrt new plates, since those would be thicker points in the crust? Maybe putting those continents more towards the middle of the plates and not crossing plate boundaries since plate convergences hasn't happened yet.

Thank you so much!

Help a teacher out. I’m an elementary teacher without a science background. I do enjoy teaching science to my kiddos but I can’t teach science beyond 6th grade level (please keep in mind while answering). A few years ago I taught a geology unit and this past spring I taught the same unit again and remembered being confused about this question back then. So, I tried googling, I tried stack exchange, quora, everything, and NO resource could break this down for me: what in the world is the difference between metals and minerals? I know metals can be extracted FROM ores found in rocks but apparently, elements like silver, gold and copper are considered both a metal and a mineral. Are there others like this? If so, which ones? And please confirm for me: most minerals are not metals at all, but are most metals also minerals? (The science book I use, which I normally love, was talking about minerals’ qualities and showing pictures of things like chalk and limestone and then suddenly when explaining the uses of minerals, it’s taking about coins, electric wiring and musical instruments and the kids and I were all confused). I also asked the chemistry high school teacher and she wasn’t sure how to explain it.

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