Nicole delacruz Posted March 29, 2021 Share Posted March 29, 2021 So I pulled this off the side of one of our mts thinking I had a geode but it does not look like it. Any ideas or suggestions? Link to comment Share on other sites More sharing options...
Top Trilo Posted March 29, 2021 Share Posted March 29, 2021 Looks like a concretion 1 1 “If fossils are not "boggling" your mind then you are simply not doing it right” -Ken (digit) "No fossil is garbage, it´s just not completely preserved” -Franz (FranzBernhard) "With hammer in hand, the open horizon of time, and dear friends by my side, what can we not accomplish together?" -Kane (Kane) "We are in a way conquering time, reuniting members of a long lost family" -Quincy (Opabinia Blues) "I loved reading the trip reports, I loved the sharing, I loved the educational aspect, I loved the humor. It felt like home. It still does" -Mike (Pagurus) “The best deal I ever got was getting accepted as a member on The Fossil Forum. Not only got an invaluable pool of knowledge, but gained a loving family as well.” -Doren (caldigger) "it really is nice, to visit the oasis that is TFF" -Tim (fossildude19) "Life's Good! -Adam (Tidgy's Dad) Link to comment Share on other sites More sharing options...
Darktooth Posted March 29, 2021 Share Posted March 29, 2021 Sometimes they form around a fossil. There could be one inside it if you want to whack it with a chisel and hammer. I like Trilo-butts and I cannot lie. Link to comment Share on other sites More sharing options...
Ludwigia Posted March 29, 2021 Share Posted March 29, 2021 According to petrological definition, a geode IS a concretion. They can contain agate, for example, or as mentioned above, fossils. A geode with crystals in a cavity is called a druse. They can also, as appears to be the case here, often simply be filled with sedimentary stone. 2 Greetings from the Lake of Constance. Roger http://www.steinkern.de/ Link to comment Share on other sites More sharing options...
DPS Ammonite Posted March 29, 2021 Share Posted March 29, 2021 30 minutes ago, Ludwigia said: According to petrological definition, a geode IS a concretion. They can contain agate, for example, or as mentioned above, fossils. A geode with crystals in a cavity is called a druse. They can also, as appears to be the case here, often simply be filled with sedimentary stone. A geode is not a concretion. A concretion is a mass of rock and mineral particles that are cemented together by a mineral or minerals. Calcite, iron oxide and silica are common. Concretions are usually solid. A geode is a rock that can separate from the matrix which contain minerals that are deposited inside a cavity. Geodes are or were at one point hollow. Mindat is a great resource for geological/mineralogical definitions. https://www.mindat.org/glossary/geode https://www.mindat.org/glossary/concretion 2 My goal is to leave no stone or fossil unturned. See my Arizona Paleontology Guide link The best single resource for Arizona paleontology anywhere. Link to comment Share on other sites More sharing options...
Sjfriend Posted March 30, 2021 Share Posted March 30, 2021 A good rule of thumb to give an idea if it is geode is weight. Does it feel like it is an appropriate weight for its size? If very light for its size then good call to cut open with rock saw to see if hollow. If heavy then smack with a hammer and chisel to see if solid or fossil inside. Only one way to know for sure and have a go at it lol Link to comment Share on other sites More sharing options...
Ludwigia Posted March 30, 2021 Share Posted March 30, 2021 13 hours ago, DPS Ammonite said: A geode is not a concretion. I was just mentioning the accepted, although controversial, petrological definition of geode. 1 Greetings from the Lake of Constance. Roger http://www.steinkern.de/ Link to comment Share on other sites More sharing options...
Nicole delacruz Posted March 30, 2021 Author Share Posted March 30, 2021 I think it is a concretion thank you for pointing me in the right direction. 1 Link to comment Share on other sites More sharing options...
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