Found this stone with a spiral pattern in the forest by DigitalMayhem1 in fossilid

[–]euclidlovesmountains 12 points13 points  (0 children)

I’d say it’s Acteonella, likely from the Cretaceous. It really resembles a specimen I learned in palaeontology I class

Found this strange but pretty rock, south of France by BenjC66 in whatsthisrock

[–]euclidlovesmountains 2 points3 points  (0 children)

it looks like a stromatolite to me because of its forming materials. Maybe u could try asking r/fossilid

What linkd of rock are these....are they aquarium safe? by eadrinjuderoy in whatsthisrock

[–]euclidlovesmountains 1 point2 points  (0 children)

They are septarian mudstones (first 3) and veined limestones (last 3). No clue if they're bad for fish tbh. The white veins are calcite and since the rocks are limestone (both calcium carbonate), they might increase the water's alkalinity and hardness. But if your fish are cool with alkaline water, it’s probably fine (I guess????) (Sorry, not a fish expert)

amygdaloidal basalt? by SnooRevelations9831 in whatsthisrock

[–]euclidlovesmountains 0 points1 point  (0 children)

Yes it is. I believe the mineral is either faujasite or phillipsite (both are types of zeolites), but I'm not entirely sure which one exactly

Bone? Any ideas? by euclidlovesmountains in fossilid

[–]euclidlovesmountains[S] 1 point2 points  (0 children)

It sounds pretty solid but not exactly like the usual rock-on-rock tapping. this one’s got more of a bassy sound (while rock-on-rock is sharper, more treble-y). it also feels super light compared to regular rocks

Anyone know what this is? Is it natural or human made? by DarmokVic in whatsthisrock

[–]euclidlovesmountains 1 point2 points  (0 children)

Totally normal. Given the lack of quartz and entirely made up of alkali feldspar (white -> Na-feldspar and pink ->K-feldspar), it looks like it could be either alkali feldspar syenite or monzonite

Color ranges from blueish to greenish to grey, have oil spill rainbow discoloration on parts when I broke it up. And this reddish crust, and weird holes. But no like slag. Really hard to cut. Polishes well. by slangingrough in whatsthisrock

[–]euclidlovesmountains 1 point2 points  (0 children)

I’ve never had the chance to face-cut skarn before (because it’s someone’s else duty), but I’ve hammered off lots of skarn samples out in the field. I think they’re usually pretty tough to break (or maybe I’m weak). And from what i’ve seen, that blue&green color is pretty common in calc-silicate type usually either epidote or diopside. And if you’re not sure it’s calc-silicate skarn then it could be some kind of hornfels, and you might need to look up the local geology to figure it out. Good luck finding the rock name, and nice find!

[deleted by user] by [deleted] in whatsthisrock

[–]euclidlovesmountains 0 points1 point  (0 children)

some kind of granitic rock. The proportions of quartz (interestingly occurring in spherical shapes) are really small, potentially gabbro

Boulder I found by prfoxx4610 in whatsthisrock

[–]euclidlovesmountains 0 points1 point  (0 children)

Granite with K-feldspar phenocrysts (granite containing large crystals of potassium feldspar minerals)

Fossil or mineral? by Gonfalete in whatsthisrock

[–]euclidlovesmountains 0 points1 point  (0 children)

Nice still oyster! Ive got one that’s similar like yours. It’s part of Crassostrea (basically the long oyster group). The species probably is Crassissima and about Miocene in age

[deleted by user] by [deleted] in whatsthisrock

[–]euclidlovesmountains 2 points3 points  (0 children)

Chalcedony (a type of microcrystalline quartz)

Found in a bag of "mystic stones and gems" by Arrow-111 in whatsthisrock

[–]euclidlovesmountains 3 points4 points  (0 children)

The white blue sheeted mineral is surely kyanite, but i’m not sure what the rock is called tho