FMF - Friends of Minerals Forum, discussion and message board

[Brandonh]

I found a bunch of geodes while looking for fossils in a new lake that was being dug in Venice, Florida. They were located under a clay shelf with what I'm assuming was an old reef. They are yellowish gold. I believe they are calcite, but was wanting to know the type.
If anyone knows that would be awesome!

[Bob Harman]

Not being a Florida expert, I can only hazard a guess based on your photos and what little I know.

I think you have found portions of Calcite cave speleotherms and cave stalactites. These have to do with reefs and sedimentary type caves where they have grown.
Many similar examples come from Citrus County, near the Town of Lecanto, about 100 miles directly North of your find.

Larger intact examples might look like cave structures, but smaller examples including cross sections, and the tips of the structures might resemble geodes which they technically are not.
The central portion of cross sections would be hollow, as they are tube like structures with some poorly formed crystal tips pointed into the central tube hollow.

To test for them basically being calcite, soak one of your lesser examples in vinegar for 10 -15 minutes to see if it fizzes and starts dissolving.

Nice find and hope this helps, Bob

[Brandonh]

Thank you very much. This has to be the most insightful answer I have had so far on what they are. If it's alright I would like to share more pictures of what I have found. I really didn't hold back on what was there. Cave formations sounds like a great clue.
Stand by, I will share more pics. I've been very confused on all the different things I have found.

Any idea the name of the calcite?

[Tom Tucker]

Brandon, your specimens certainly look like the mineral calcite, but I don't think they have any thing to do with caves or speleothems. More likely they were formed as nodules or concretions , or dare I say it - geodes, but without any quartz exterior rind, perhaps in the clay beds you mentioned. I've been in caves in Florida, with very beautiful calcite formations, and even calcite crystals, but none of them are similar to your rocks. Tom

[Brandonh]

Awesome thank you for the response.
I am going to attach additional photos I just took.
I have collected a few of these and get to break them open. I am going to attach a before and after pic.

I really appreciate all the input. I am normally hunting fossils and these just popped up and caught my interest. Maybe I've overlooked them in the past, but never really see much of them in my area.

[Brandonh]

After opened

[Brandonh]

#2

[Brandonh]

After

[Brandonh]

Here's the lot of them

[Brandonh]

Here's one cut w tile saw

[Bob Harman]

I'll amend my original interpretation of your examples to agree with Tom T.

I agree that they look like calcite nodules. In the broad sense of definitions, they would be considered geodes, but in the strict definition of what a "geode" is, they might not fit.
Anyway that is a matter of definition, not affecting what you have found. Nice finds! Bob

[Kevin Schofield]

[Brandonh]

Thank you for taking the time and thorough answer. I appreciate everyone's input, I've been twisting and turning trying to find an answer. I also found some much larger pieces, that I'm guessing are the the same after looking around at the internet for "concretions" . They are bulbous but much larger. I couldn't help myself to grab asuch as I could before they got crushed and turned into a road. The pet shop guy I sell them to will be happy to know.
I will attach a couple pictures.

[Brandonh]

Here is one of cluster

[Brandonh]

A bunch I collected