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  Author   Comment  
Lori Garza
 #1 
Hi! I was wondering.. How do you Identify geodes? What do they look like before you crack them open? I live in Texas.
Mike Streeter
 #2 
Hi Lori,

Geodes are generally round or roundish hollow mineralized rocks that are distinct from the rock in which they form. Their surfaces are often irregular and knobbly, but can be smooth. They outer surfaces sometimes show veining, an indication of interior mineralization. Since their exteriors are harder than the rock in which they form, they are more resistant to weathering and erosion making them stand out in outcrop or even when mixed with other rocks when loose on the surface. With all this said, the best way to learn to recognize geodes is by experience collecting them. So, find a place where they are known to be plentiful, and go for it!

By the way - rocks that look and form like geodes, but are not hollow are called nodules or concretions.

Mike
gemhunter
 #3 
Hi Lori,

There is a new book out called Geodes Nature's Treasures by Brad Cross & June Culp Zeitner. It is a very well written book on Geodes and it has a lot of photos in it to showing what Geodes look like from different areas. KOR
maliya
 #4 
hello,

I was wondering how you can tell if it is a geode from the outside?
I was also wondering what kind of environment geodes grow in?
Mike Streeter
 #5 
As I wrote before, geodes are generally round or roundish hollow mineralized rocks that are distinct from the rock in which they form. Their surfaces are often irregular and knobbly, but can be smooth. They outer surfaces sometimes show veining, an indication of interior mineralization. Since their exteriors are harder than the rock in which they form, they are more resistant to weathering and erosion making them stand out in outcrop or even when mixed with other rocks when loose on the surface. In most cases, you have to crack or cup open a potential geode to see if it in fact hollow. Sometimes a geode will rattle if it is really how and there are loose pieces of rock or mineral inside. Geodes are also lighter than a concretion or nodule of the same size.

Geodes can form in gas bubbles in igneous rocks or in rounded cavities in sedimentary formations.

Mike
Skip scarpa
 #6 
Found out this might be a geode. Live on an island and this was shipped in by father in train car of rocks 26 years ago. What to do? It's about 2' in diameter. I can send photo.
Mike Streeter
 #7 
Skip,

You can post a photo on this board or email it to me at mcstreeter@charter.net

Mike
lapidaryrough
 #8 

Geodes come in other FORMS / solid !!! - Brazilian agate gas pocket fill with sedimentation, or hollow with - what ever you find in them. 

I have found mud,   loose  quartz in Brazilian. and  water in a lot of them.

Lebanon,Oregon agate  - Geode. / seam agate

and the upper slag zone of lava flows where the gas pockets form for the sedimentation in solution to fill the geode cavity  hollow or  Solid. 

 

 

Jack

 

Ashlee
 #9 
My rock is hard to break and it does look like a geod but I don't know if its a geodes
Bob Harman
 #10 
ASHLEE,    As MIKE STREETER and other previous posters have said, there are geodes and other look-a-like rounded rock masses including nodules, concretions, and agates.   To be strongly considered a geode, it should have been found where geodes are known to occur. There are a number of threads on the website that discuss where geodes are found in both the Midwest and West; also where they are not expected to be found. Search these discussions and compare to where your example was found.
If it is any of the above rock structures, generally it will only break with ease if it is hollow. Forms of any of the above will be difficult to near impossible to break if they are solid or nearly so. This is especially true with larger examples and those composed of hard and resistant minerals like quartz. Lots of pounding is needed to break these; sometimes even after pounding, the solid example might just break off a piece rather than break cleanly thru the center.
So, if you have an example that won't readily break, it is probably solid and of a hard resistant mineral. It may or may not be a geode.     Hope this helps.     BOB
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