Greetings @nick-polglaze and @chloe-geddes! I am afraid that this is not a fossil at all but instead a specimen of andesite (igneous – lava). The large white masses appear to be orthoclase phenocrysts (large crystals), but that is slightly difficult to tell in an image.

Greetings @sara-andrade! This is a beautiful ammonite specimen! This is likely a rather popular Cretaceous specimen but the image is too blurry for me to tell much more. Could you please provide more images along with a scale? Thanks!

Greetings, @noah-haumann! Erosion refers to all processes breaking down rocks, such as water tumbling a rock in a stream smoothing the rock or breaking the rock by smashing it on other rocks. The erosion lines the others are referring to resulted from some action that somehow carved a line into the rock.

Greetings @jack-parker-tyreman, @nina-hotov, and @smudge-smith! I agree that this is simply a rock, most likely vesicular basalt. The holes are vesicles caused by the release of volatile gas ascending through the basalt lava, leaving the conduits preserved when the lava solidifies. This is corroborated by the presence of white feldspar crystals…[Read more]

Greetings, @paolo-covelli and @a-trilobite! This is a lovely Scaphites specimen! Scaphites is a popular genus of Cretaceous ammonites.

Greetings, @diane-soderman! I believe this is a piece of highly weathered petrified wood. The specimen is clearly well-infiltrated by quartz minerals and has the general shape suggestive of petrified wood. The material encasing the specimen appears to be sand and pebbles cemented together, as if this petrified wood was part of a conglomerate and…[Read more]

Greetings @a-trilobite and @daniel-park! Where did this information come from? I would be very wary of the information if it is not from credible, mainstream source. Remember that because of the complexity of evolution, the same organisms will likely never evolve into the same form twice. For example, if a trilobite were to evolve on Earth it…[Read more]

Greetings, @moosa-kindi! I agree with @daniel-park that this specimen is likely a pelecypod of genus Gryphaea, sometimes called “Devil’s Toenail”.

Greetings, @mike-steinhorst! I doubt it could be a “hinge of an ancient Gastropod” because this specimen would have a more concavo-convex geometry in addition to a different texture.

Great specimen, @evan-walsh!

Greetings, @mike-steinhorst! When I first saw this picture, I thought it was vesicular basalt lava, but it is difficult to tell from the angle of the photograph. Could you please provide pictures with several angles and one where we can see the entire specimen? Thank you!

Greetings, @elizabeth-henson and @samantha-ocon! I concur that this is not petrified wood; chert seems to be a reasonable possibility.