not sure what these crystal like rocks I found in texas?

Mr Chris

Jr. Member
Oct 15, 2010
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I went out today looking for Indian artifacts and found these crystals I think that's what they are. Some look more like crystals some look like clear glass almost, with some debris suspended in them and some have a real opal look / mother of pearl appearance. I want to add a little info: I found these in a field where there had been some serious excavation for a new subdivision going up. We had rain last night and I was trying to find a place to hunt for arrowheads etc. which I am quiet knowledgable about. However after striking out on the indian artifacts I started seeing more and more of these in the piles of the dirt they had been moving. I have very limited experience hunting this area of North Texas ( Denton County) so I don't know what is common here. I did try and look at the Texas site of rocks and Minerals and did not find anything that really looked like my samples. I apologize ahead of time for my novice at best post . Any help that I get will be greatly appreciated . Thank you
 

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I went out today looking for Indian artifacts and found these crystals I think that's what they are. Some look more like crystals some look like clear glass almost, with some debris suspended in them and some have a real opal look / mother of pearl appearance. I want to add a little info: I found these in a field where there had been some serious excavation for a new subdivision going up. We had rain last night and I was trying to find a place to hunt for arrowheads etc. which I am quiet knowledgable about. However after striking out on the indian artifacts I started seeing more and more of these in the piles of the dirt they had been moving. I have very limited experience hunting this area of North Texas ( Denton County) so I don't know what is common here. I did try and look at the Texas site of rocks and Minerals and did not find anything that really looked like my samples. I apologize ahead of time for my novice at best post . Any help that I get will be greatly appreciated . Thank you
When attempting to identify any crystal your first step should be to identify its hardness, it can narrow the field a lot. An easy way is to use your fingernail then a penny. A piece of glass. Then a standard carpentry nail. The objective here is to see what object will scratch your crystal and what one will not. Be sure to do your tests in an inconspicuous place on your crystal incase it's valuable.
 

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Thank you for taking the time to reply, I am always wanting to learn and any proper info is much appreciated. These scratch with a finger nail not real easy but they do scratch. So i am guessing that i found a bunch of salt? LOL
 

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is it soft?..I know when i was in Sunth Texas last March, i found a HUGE hole in the side of a mountain that had Crystals all inside it....I think it turned out to be Gypsum..might wanna dbl check thou...Still a cool find!

Gypsum is a mildly soft mineral
 

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Thank you for taking the time to reply, I am always wanting to learn and any proper info is much appreciated. These scratch with a finger nail not real easy but they do scratch. So i am guessing that i found a bunch of salt? LOL

NaCl (sodium chloride)=Salt, is super easy, just lick it, if it's salty, then you've got salt. And Halite or common rock salt is almost always cubic in habit.
But gypsum/selenite also has a hardness of 2, it scratches very easily with a fingernail, calcite however has a hardness of 3 and it will scratch with a
fingrernail, but not real easy, so that's why I'm thinkin you got calcite.

RH
 

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I went out today looking for Indian artifacts and found these crystals I think that's what they are. Some look more like crystals some look like clear glass almost, with some debris suspended in them and some have a real opal look / mother of pearl appearance. I want to add a little info: I found these in a field where there had been some serious excavation for a new subdivision going up. We had rain last night and I was trying to find a place to hunt for arrowheads etc. which I am quiet knowledgable about. However after striking out on the indian artifacts I started seeing more and more of these in the piles of the dirt they had been moving. I have very limited experience hunting this area of North Texas ( Denton County) so I don't know what is common here. I did try and look at the Texas site of rocks and Minerals and did not find anything that really looked like my samples. I apologize ahead of time for my novice at best post . Any help that I get will be greatly appreciated . Thank you

I think you have gypsum. You can do a simple test to figure out if its calcite. Put the specimens in a bowl. Pour some vinegar over the specimen. If the specimen reacts with the vinegar then it's calcite.
 

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Thank you for all the replies.Its definitely not salt. I am out of vinegar until I go to the grocery store later then I will try that test. Once again Thanks for all the help.
 

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Ok it doesn't react with vinegar. Now on to todays find in a different field , a few mile's away from first field. I found a much bigger piece of a similar type rock, however it is much harder (can't scratch with fingernail) , it also seems to have a second type of rock in it that is not crystal like at all. It allows light to shine through some. The second rock is like a light rootbeer color when I light it up with a flashlight. The rock I found today came from a field where they are moving a massive amount of earth to build what is the largest retail development in the country currently. its approx 2 1/2" x 1 3/4". Now if one of you guys with a wealth of knowledge could help identify this without making me feel too dumb I would appreciate it. So far I know its not salt or calcite. Thanks in advance for any help. WP_20131019_043.jpgWP_20131019_041.jpgWP_20131019_055.jpg
 

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Its........
Calcite
Very common in limestone old sea shells and other old sea bed material.
Florida..where I am...like large portions of Texas have loads of it.
It's also common on construction sites because its found in the limestone drain rock that's used for laying pipes.
I thought I said Calcite once already ...no tests necessary.
 

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Its........
Calcite
Very common in limestone old sea shells and other old sea bed material.

In his last response the mineral didn't have any reaction to vinegar. If it doesn't have at least a minor reaction to vinegar then it's unlikely its calcite.
 

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I even see the limestone it's in.
Look at the photos of his and mine.
Okay I'll go put mine in vinegar
 

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In his last response the mineral didn't have any reaction to vinegar. If it doesn't have at least a minor reaction to vinegar then it's unlikely its calcite.

Do you have a piece of calcite?
If so try yours.. I have a bunch..and vinegar does nothing.
It softens the surrounding material but does nothing to the crystal but clean it.

View attachment 884281
 

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What you have found is Gypsum, not Calcite. Here in Montana we find a lot of it it in the bad land areas.


16596523.jpg GypsumSeleniteCrystals.JPG
 

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Ok it doesn't react with vinegar. Now on to todays find in a different field , a few mile's away from first field. I found a much bigger piece of a similar type rock, however it is much harder (can't scratch with fingernail) , it also seems to have a second type of rock in it that is not crystal like at all. It allows light to shine through some. The second rock is like a light rootbeer color when I light it up with a flashlight. The rock I found today came from a field where they are moving a massive amount of earth to build what is the largest retail development in the country currently. its approx 2 1/2" x 1 3/4". Now if one of you guys with a wealth of knowledge could help identify this without making me feel too dumb I would appreciate it. So far I know its not salt or calcite. Thanks in advance for any help. View attachment 884262View attachment 884263View attachment 884264




This piece may be calcite, if it is a harder material. Gypsum, when hammered/pulverized will have a very fine powdery consistency, feeling slick when rubbed between the fingers. Calcite is much more grainy when broken down.
 

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Its........
Calcite
Very common in limestone old sea shells and other old sea bed material.
Florida..where I am...like large portions of Texas have loads of it.
It's also common on construction sites because its found in the limestone drain rock that's used for laying pipes.
I thought I said Calcite once already ...no tests necessary.
I just wanted to clear one thing this is a new construction site on virgin land no existing drainage pipe. Also thanks again for taking the time to answer and re answer my amateur questions.
 

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