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Hello all,

We were going through a collection of rocks we've collected throughout the years and came across this. What do you all think? It is non-magnetic, could it possibly be tektite or a potential meteorite?

 

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Thank you for your response! We originally thought that as well, but after looking into it the size nor the region seemed to match either. We found this in Florida. I've included an image to reference size. Any other ideas as to what it could be?

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  • 4 years later...

If you are finding rocks that are out of place in a marine formation, There are a couple natural explanations of what it can be. One is a deposit formed from a turbidity current which is an underwater landslide that comes off the continental shelf and brings mixed material down to lower levels. It gets uplifted as part of the new formation and can contain river rock or anything else stuck in the original flow.

Another cause, more rare than turbidity currents, Is that it is a gastrolith (rocks stuck in the stomach of a large marine animal) or a rock that was stuck in the baleen of whales mouth. Humpback whales and some others drag their mouths along the bottom to pick up food and sometimes get rocks stuck in baleen. They grind away and become smooth over time and when the whale dies,  the rocks are released or fall out on the ocean floor. I found one that looks similar to this that was in a massive siltstone marine formation, near some fossil whale bones as well. There’s only one way that rock got there and it was in the dead whale.

I’m not sure about natural obsidian in Florida, but you certainly have a lot of marine deposits, maybe obsidian came from somewhere else this way.

It could’ve also been what is called a manuport.  Native Americans dropped it there. If it is obsidian, which it does look like, that would have been a valuable rock for trade and I think it was probably the most likely scenario of how it got there.

Edit: Nice specimen photos by the way.

Edited by GotAU?
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Where I hunt obsidian there are other opaque nodules that look just like obsidian on the outside. But they are much harder and heavier. Much less silica content. 

I have always called them basanite. There is no olivine within 25 miles and they come out of a strata of caliche and cemented gravels. So im not sure if it actually is basinite. But it isn't obsidian.

Anyhoo you can't tell the difference sometimes visually. They look exactly like an obsidian nodule. But as soon as you pick them up you realize they are too heavy. They are opaque and not glassy at all when polished. They are just dense black silica rich basalt.

I don't think the rock in the photo is glass. I think it is heavier and harder than obsidian and is one of those other opaque black basalt like minerals. 

The surface weathering just looks like one of those "other" nodules that I call basanite.

 

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Here's the one I found.  Very heavy and hard.  Measures about 2.2"dia, .2Kg.  Sent the pics to the Geological survey.  They really had no idea what it was.  Said they thought it might be man made.  

Photo 1.jpg

Photo 2.jpg

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Is it broken or bashed on one end?  Looks like a good hammerstone.  Lots of those are manuports

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2 hours ago, Morlock said:

I find that very hard to believe.

 

6 hours ago, EgonD said:

Sent the pics to the Geological survey.  They really had no idea what it was.  Said they thought it might be man made.  

It has been my experience that the folks at USGS have very little experience at mineral ID. They just don't do much of that.

They are young college educated surveyors and geologists for the most part. They make and modify maps. They do sounding and monitor instrumentation. 

They don't identify rocks. That is just not their bag baby.

The last job I worked on I had 3 "geologists" as co workers. None could identify common minerals. Only one could tell limestone from granite. Not a single one of them had ever gone out and tried to identify rocks they had picked up.

Over the years I have met dozens of professional geologists. The only ones who knew anything about geology worked in the petroleum industry and their expertise was limited to that scope. You could show them a gold nugget or a chunk of sulfide ore and they couldn't tell what it was.

Rock hounds have consistently been the best source for mineral ID in my experience. All the geologists I have ever known were clueless. Im sure there are some really brilliant geologists out there. But I certainly have never met one who had more than a cursory grasp of basic mineral ID.

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18 minutes ago, GotAU? said:

Is it broken or bashed on one end?  Looks like a good hammerstone.  Lots of those are manuports

Fun fact!

Hammer stones are generally sandstone. Material like that would just produce crushed platforms if used as a hammer stone. It is much harder and tougher than glass. A hammer stone must be softer and less durable than the material you are working with. Preferably rough and abrasive with sharp edged particles.

I agree this object may be a manuport. But it does not fit the description of a hammer stone IMHO.

 

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55 minutes ago, Bedrock Bob said:

 

It has been my experience that the folks at USGS have very little experience at mineral ID. They just don't do much of that.

They are young college educated surveyors and geologists for the most part. They make and modify maps. They do sounding and monitor instrumentation. 

They don't identify rocks. That is just not their bag baby.

The last job I worked on I had 3 "geologists" as co workers. None could identify common minerals. Only one could tell limestone from granite. Not a single one of them had ever gone out and tried to identify rocks they had picked up.

Over the years I have met dozens of professional geologists. The only ones who knew anything about geology worked in the petroleum industry and their expertise was limited to that scope. You could show them a gold nugget or a chunk of sulfide ore and they couldn't tell what it was.

Rock hounds have consistently been the best source for mineral ID in my experience. All the geologists I have ever known were clueless. Im sure there are some really brilliant geologists out there. But I certainly have never met one who had more than a cursory grasp of basic mineral ID.

I agree that most geologists might not be able to identify rocks and minerals but anyone with intelligence can look at that photo and tell you it's not man made.

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23 minutes ago, Morlock said:

I agree that most geologists might not be able to identify rocks and minerals but anyone with intelligence can look at that photo and tell you it's not man made.

Yes. I agree.

If I ask a plumber about an electrical issue I may get a clueless answer.

If I asked a diesel mechanic how to run a trotline he might respond with something way out of left field.

If you ask a geologist to identify a stone you should expect that his answer may be off a bit. 

Guys don't like to admit they don't know. Especially when others think they should know. 

The only reason someone would ask "the geological survey" about rock ID is because they work for an organization with "Geological" in the title. The assumption is that they should know. That assumption is probably a bad one.

Im sure that the answer they got was something the guy thought camoflauge his lack of knowledge on the subject. Most of these whippersnappers at the USGS are young career guys fresh out of college and have no experience outside of college and that one organization. They spend much more time identifying and classifying beard balms than rocks.

So im not surprised that they got the answer that they did. It is pretty sad that an employee of the USGS can't tell a common rock nodule from an artifact even if rock ID is not their field of expertise. But that is the world we are living in today. 

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Thanks for all the responses!  I guess it's just a cool rock, huh?  I didn't figure the USGS guy knew what he was talking about.  I have to admit that I don't know much about these things, but I'm learning.  

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