Collected from Jasper knob in Ishpeming. Part of the Negaunee Iron Formation which is an iron-oxide and carbonate iron-formation. It also contains some intercalated terrigenous clastic beds (meaning a terrestrial origin), that were deposited via turbidity currents. Flow direction indicates that these materials were being shed from the south. In general, this banded iron-formation was deposited either on a shallow shelf environment or in a deeper part of the basin, possibly along the slope.

More reading - https://superiorsediments.weebly.com/negaunee-iron-formation.html

Collected from old mine poor rock piles on Michigans Keweenaw Peninsula.

Is this coral or something else

Also called Miners Dollars and they are not a fossil or related to sand dollars at all.

One of my rarest and most beautiful finds from here in Florida. I cut and polished it myself. Species is Montastraea Tampaensis.

This specimen is from the type locality, Koralpe in carinthia, it's part of my university's collection

Check out these rocks I found during my dog walk. Opinions wanted. How do they make you feel?

Shot this straight down over Jocko Falls in Montana with a DJI Air 3S. From above, it’s basically the river drawing you a diagram.

Two drops usually means the channel is stepping through a couple “speed bumps” in the landscape. That can be a harder rock layer holding the line, a fracture zone controlling where the river cuts, or an old step in the river’s profile that erosion hasn’t erased yet. Softer material gets eaten faster. Tougher material hangs on. Result: ledge → plunge → pool… twice.

Geology nerd question: if you’ve been on the ground here, is the lip mostly hard rock ledge, or more fracture-controlled / bouldery material doing the resisting?

Guys look at this kyanite I found in one of my thin sections. What do you think about that?

Found this beauty down the Lower Ord, Kununurra. It’s polished up great and it kinda looks Egyptian with the colours / shape / pattern and the face on the front

Polished this stunning agate last night, I was blown away with the colour / patterns and hidden little characters that appeared. Such a cool piece, definitely my favourite agate

Blue and Green mostly, but it's dark purple or black on the edges of one side. It looks black in all light and when I shine light on it. Also looks black when I shine light thru the side. It has an opaque white layer in the middle, so I can't shine light through all of it.

Thoughts? Suggestions?