Does anyone know what these rocks are? Please any info welcome

In summary,The two people exchanged arrowheads and found that they were of different types and materials. One was made of obsidian, while the other was made of different stones.
  • #1
Kstarlove1728
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I am so curious as to what I actually have found any input welcome please and thank you
 

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  • #2
Welcome to PF.

The more information you give us, the better the chance that we can help. Where did you find them? What area of what country in what kind of surroundings?
 
  • #5
berkeman said:
Welcome to PF.

The more information you give us, the better the chance that we can help. Where did you find them? What area of what country in what kind of surroundings?
I am in North America. Texas. City of san Antonio. I found all of this plus so much more in my back yard while digging up a place for a garden and now that I'm paying attention my whole entire property is LITTERALY covered in all kinds of different rocks and gems I believe of such as posted. I am very curious and would love to investigate and find out more about them. I have more stuff if you would like more images. Let me know thank you so much!
 
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  • #7
The San Antonio area contains limestone and many gravels and slope deposits that could originate from far upstream. Since most of the stones have a deep weathered crust they have been near the surface for a long time, but not in an active stream that would knock off the oxide jacket.

The first is green and it looks like it is the only wet sample. It could be a serpentine or igneous rock. Since it has rounded corners I think we can rule out green flux from a metal smelter or refinery that would be crushed for road base.

Fine grained stones with a thick weathered outer layer are very hard to identify without a clean fracture surface, a hardness scratch test, and a drop of acid to test for carbonate or limestone.

Get a copy of your local geology map from the USGS. Then you can look for the rock type in your location. My guess is you are on the valley floor with “Quaternary gravels”.
 
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  • #8
berkeman said:
So is that obsidian, or were arrowheads made out of different material in different parts of the continent?
From https://www.nature-watch.com/images/Arrowhead Article.pdf

Most arrowheads were made from various stones such as flints, obsidian, and chert; however, wooden and metallic ones have also been found.
 
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  • #10
I used to find obsidian pieces near my high school home in the Napa Valley, but I don't think I ever found a real arrowhead. That must be a pretty special moment to find a piece of history like that. :smile:
 
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  • #11
berkeman said:
I used to find obsidian pieces near my high school home in the Napa Valley, but I don't think I ever found a real arrowhead. That must be a pretty special moment to find a piece of history like that. :smile:
Most of mine were found by my Grandfather at his farm in Arkansas. I have lots that I should add to my board:
arrowheads.jpg
 
  • #13
berkeman said:
So is that obsidian, or were arrowheads made out of different material in different parts of the continent?:smile:
I'm not sure and it's possible I guess but this is stuff from about 6 inches to 10 inches under the soil slot from only 3 or 4 inches I have not even dug farther than a foot but it's from all different areas and I only have about an acre so it's LITTERALY everywhere everything varys so I'm not sure what kind of rock but I'm doing research and it's definitely flint maby pre paleolithic what do you think? It's all weird some looks like gold ore and others have gems I think inside the actual rock and my tree was hit by what I thought was a lightning strike twice in the same spot in the past 7 years. But more studies show a meteor shower around 2019 so I'm thinking some fall off debris from that but twice hit? I'm questioning everything now I'll put some more pics of stuff. I have 5 gallon buckets full of various stuff it's so so cool 😎 thanks guys I appreciate it so much
 
  • #14
berkeman said:
I used to find obsidian pieces near my high school home in the Napa Valley, but I don't think I ever found a real arrowhead. That must be a pretty special moment to find a piece of history like that. :smile:
I have so much it's unreal! I want to just keep digging. I actually found a bone I'll show you maby you can tell me how old or what species it is close to?
 
  • #15
Baluncore said:
The San Antonio area contains limestone and many gravels and slope deposits that could originate from far upstream. Since most of the stones have a deep weathered crust they have been near the surface for a long time, but not in an active stream that would knock off the oxide jacket.

The first is green and it looks like it is the only wet sample. It could be a serpentine or igneous rock. Since it has rounded corners I think we can rule out green flux from a metal smelter or refinery that would be crushed for road base.

Fine grained stones with a thick weathered outer layer are very hard to identify without a clean fracture surface, a hardness scratch test, and a drop of acid to test for carbonate or limestone.

Get a copy of your local geology map from the USGS. Then you can look for the rock type in your location. My guess is you are on the valley floor with “Quaternary gravels”.
Oh and it's wet because I washed it. We are near a creek but it's about 2 Miles and I'm in a really suburban area so that's even more confusing. How exactly do I do such test? And I can break any of them open for you I have more pics so just tell me what to do and I will do my best. Thank you all so much
 
  • #16
Some more stuff maby this helps I'll do one more set hopefully that's going to be helpful
 

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  • #17
Cool stuff
 

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  • #18
berkeman said:
So is that obsidian, or were arrowheads made out of different material in different parts of the continent?
I wouldn't think, so as I believe that obsidian is usually black, but I could be wrong on this.
Most arrowheads were made from various stones such as flints, obsidian, and chert; however, wooden and metallic ones have also been found.
Obsidian was also used in places where it could be found or was traded for. It can be flaked into extremely sharp edges. California used to have many volcanoes, and still has a couple of newer ones (Shasta and Lassen) in the north part of the state. Some of the former volcanoes could have erupted lava that cooled quickly to form obsidian. It's also present in many parts of the Northwest - Washington, Oregon, and other states. I wouldn't think there would be a lot of obsidian in Texas, but New Mexico had a number of volcanoes or vents in the past, as did Arizona.
 
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  • #19
Kstarlove1728 said:
Cool stuff
The samples have been weathered heavily near the surface, or are the product of groundwater circulation during weathering. You must download the USGS geology map that covers your site to identify the type of erosion and so the original source.
...8272.jpg foreground, looks like a calcareous concretion that formed in soil during weathering.
...8815.jpg could be a lump of calcite or quartz. Test it with an acid or try to scratch it with steel.
...9568.jpg yellowish in background, does it feel soft and slimy like soapstone, if so it is talc, a weathering product.
 
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  • #20
http://www.thefossilforum.com/index.php?/topic/52308-a-comprehensive-guide-to-the-cretaceous-strata-of-the-greater-san-antonio-area-how-to-read-the-rocks/
 
  • #21
Baluncore said:
The samples have been weathered heavily near the surface, or are the product of groundwater circulation during weathering. You must download the USGS geology map that covers your site to identify the type of erosion and so the original source.
...8272.jpg foreground, looks like a calcareous concretion that formed in soil during weathering.
...8815.jpg could be a lump of calcite or quartz. Test it with an acid or try to scratch it with steel.
...9568.jpg yellowish in background, does it feel soft and slimy like soapstone, if so it is talc, a weathering product.
It's not soft it's rather hard and durable I am thinking a lot is quartz but some has like gemstones stuck inside whatever material it is it's odd idk but cool nonetheless thanks so much for all the help
 
  • #22
Some more
 

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  • #23
Does anyone else think this looks like rock art? Too neat if nothing at all still looks wicked I think
 

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  • #24
9381.jpg smells like a scaphopod. https://en.wikipedia.org/wiki/Tusk_shell

But it is impossible to correctly identify rocks and fossils from photographs of dry weathered specimens. Context is everything. Unfortunately, the camera does not record the chemistry, size, density, or 3D shape.

What you are finding is just the beginning. Many of the stones you are selecting could be chemically resistant silicified fossils that remain in the soil, after the calcareous rock is dissolved by rainwater.

I guess you are in Cretaceous rocks. Take a look at the history of that geological period, and how it is divided and named; https://en.wikipedia.org/wiki/Cretaceous

Your next move should be to identify the name of the sedimentary formation you are sampling. To do that, find your location on the “Geologic atlas of Texas, San Antonio sheet” and identify the name of the geological formation from the code and index.

I gave you a link to an experts list on the fossilforum in my post #20.
http://www.thefossilforum.com/index...eater-san-antonio-area-how-to-read-the-rocks/
You must look at that link to identify what sort of shells you are finding from the included photographs of the specific fossils found in that formation. Each post in that thread covers fossils from a different formation, which may have taken between one and ten million years to lay down in the shallow Cretaceous sea.

Keep an open mind, as any geologic map may sometimes get it wrong or not have sufficient detail. The geological formations were originally mapped by rock type, using characteristic indicator fossils present to identify the formation and the geological time period of deposition.
 
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  • #25
Kstarlove1728 said:
I'm in a really suburban area
You might look into the construction history of your area; it is possible your yard is all fill material trucked in from a gravel pit. Not that that makes the rocks any less interesting, just that they may have been re-located.
 
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  • #26
gmax137 said:
You might look into the construction history of your area; it is possible your yard is all fill material trucked in from a gravel pit.
Visit the gravel quarries in your area, or just look at the side of the roads to get an idea of what to expect. Slope deposits suggest you should walk uphill to find the source. For stream deposits walk up the river following the pebble type that interests you to the headwater or "reef". For glacial deposits start looking 100 miles north of the border.

A good practical geology exam should always includes a subtle piece of roofing tile or concrete. It is the students ability to describe it that is being assessed, with bonus points to those who identify it as anthropocene.

… 7879.jpg (in post #17) looks like a typical Pelecypod fossil found in the Texan Cretaceous. Look it up in the fossilforum thread. You may be able to identify it as a common species and give it a name.

Study this wikipedia link carefully as it includes much of what you will find.
https://en.wikipedia.org/wiki/Bivalvia

At this stage you are a beginner to the game of fossil hunting. Once you “get your eye in” you will know what to look for, and so start to see fossils all over the place. Get down on your knees and study very carefully, the devil is in the detail.

Don't expect perfect condition in fossils found in soil, they have been waiting 100 million years, you should have got there earlier. Look for hard rock outcrops or site excavations. Get a white hardhat, it makes you look like the chief engineer and will protect your head.
 

1. What are the most common types of rocks?

The most common types of rocks are igneous, sedimentary, and metamorphic.

2. How can I identify the type of rock I have?

You can identify a rock by examining its color, texture, and composition. You can also perform simple tests like the scratch test or acid test to determine its hardness and chemical composition.

3. Can rocks have different colors?

Yes, rocks can have different colors depending on their mineral composition. For example, rocks with a high iron content tend to be red or orange, while rocks with a high calcium content can be white or light-colored.

4. Are there any online resources for identifying rocks?

Yes, there are many online resources such as geology websites, rock identification guides, and forums where you can post pictures of your rocks and get help identifying them.

5. What information should I include when asking for help identifying rocks?

When asking for help identifying rocks, it is helpful to include clear pictures of the rock from different angles, information about where and how you found it, and any other observations such as its texture or weight.

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