brenda
off to a rocking start
Member since June 2013
Posts: 10
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Post by brenda on Feb 6, 2015 13:04:15 GMT -5
Hello everyone. I'm new to rock tumbling and all of this stuff, but am loving it. I found a black rock on the beach and tumbled it just to see what it would look like. It came out extremely dark purple. The thing is, it looks black until it gets warm from my hand and the warmer it gets, the more purple. I ran it under hot water and it became a beautiful dark royal purple that fades back to black as it cools. Does anyone have any idea what I have found? Thank you in advance.
Brenda
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Post by broseph82 on Feb 6, 2015 13:07:34 GMT -5
Can you post a pic or video? Would love to see this and have one for myself!! brenda
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Post by captbob on Feb 6, 2015 13:14:08 GMT -5
Sounds like one of those old mood rings! Was it an actual "rock" you found? I'm not aware of any natural thermochromic (changes color with change in temperature) minerals. Would also like to see a picture.
And, welcome to the forum!
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Post by snowmom on Feb 6, 2015 15:35:40 GMT -5
welcome to the boards! what a fascinating first post! Glad you are with us. If not a video, then maybe before and after pictures (we LOVE pictures).Very interesting! Is it the heat, do you think, maybe moisture that makes it look different? Some minerals are very "water loving" do you happen to have a picture of what it looked like before you polished it? Somebody here will be able to come up with an answer for you, this board is such a great resource.
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Post by Pat on Feb 6, 2015 15:57:46 GMT -5
Welcome and Wow!
Yes, we need a few pictures. Never heard of this.
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Deleted
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Member since January 1970
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Post by Deleted on Feb 6, 2015 16:04:08 GMT -5
Sounds like one of those old mood rings! Was it an actual "rock" you found? I'm not aware of any natural thermochromic (changes color with change in temperature) minerals. Would also like to see a picture. And, welcome to the forum! Thanks for the new vocabulary!! Google is our friend. minerals.gps.caltech.edu/mineralogy/undergrad/garnet_2001/garnet.htmlThere must be others.
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Post by captbob on Feb 6, 2015 16:18:03 GMT -5
"The four garnets on the left display thermochromism- becoming green when heated -"
define "heated"
To change color due to the difference in air temperature and body heat, it would have to be pretty darn sensitive to heat.
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Post by deb193redux on Feb 6, 2015 16:29:45 GMT -5
I wonder if you hand was not moist, and you were really slightly moistening the stone. Dark purple could look black with a bit of surface frosting.
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brenda
off to a rocking start
Member since June 2013
Posts: 10
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Post by brenda on Feb 6, 2015 17:19:20 GMT -5
Thank you very much everyone. I'll go take pictures of it now.
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jamesp
Cave Dweller
Member since October 2012
Posts: 36,553
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Post by jamesp on Feb 6, 2015 18:23:44 GMT -5
What is your temperature ?? awaiting photos, got to see this mystery material
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brenda
off to a rocking start
Member since June 2013
Posts: 10
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Post by brenda on Feb 6, 2015 19:57:47 GMT -5
Before the heat After running it under hot water. The camera changed the color, to the naked eye, it looks royal purple. I don't have a before tumbling picture, I'm sorry.
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brenda
off to a rocking start
Member since June 2013
Posts: 10
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Post by brenda on Feb 6, 2015 20:00:18 GMT -5
Another. It was hard to capture the color
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Post by jakesrocks on Feb 6, 2015 20:50:56 GMT -5
From looking at all of the chips out of the surface, I'm guessing you have a piece of water worn slag glass. Hold it up to a bright light and check for air bubbles inside. Regardless of what it might be, it's a neat piece.
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brenda
off to a rocking start
Member since June 2013
Posts: 10
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Post by brenda on Feb 6, 2015 21:00:17 GMT -5
It doesn't seem to be translucent, I can see no air bubbles. It looks solid, the sun doesn't even shine through it, whatever it is. It's strange to me that it appears purple but blue in the camera lens.
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Deleted
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Post by Deleted on Feb 6, 2015 21:26:42 GMT -5
It doesn't seem to be translucent, I can see no air bubbles. It looks solid, the sun doesn't even shine through it, whatever it is. It's strange to me that it appears purple but blue in the camera lens. The blue color in your image may be reflection of the sky.
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Deleted
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Post by Deleted on Feb 6, 2015 21:28:03 GMT -5
"The four garnets on the left display thermochromism- becoming green when heated -" define "heated" To change color due to the difference in air temperature and body heat, it would have to be pretty darn sensitive to heat. Ohhh... So NOW you set the parameters!!!
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jamesp
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Member since October 2012
Posts: 36,553
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Post by jamesp on Feb 6, 2015 21:32:22 GMT -5
Looks like glass. It seems to have some iridescence. It way have microscopic fractures that hold moisture, then when totally dry it may get dull. The first photo seems to show a lot of surface fractures.
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brenda
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Member since June 2013
Posts: 10
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Post by brenda on Feb 6, 2015 21:41:28 GMT -5
It may be, I took the photo outside to get the best light i could.
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Deleted
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Post by Deleted on Feb 6, 2015 23:03:50 GMT -5
It may be, I took the photo outside to get the best light i could. How did I know?
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brenda
off to a rocking start
Member since June 2013
Posts: 10
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Post by brenda on Feb 6, 2015 23:30:34 GMT -5
Its very hard, I can't make a mark in it with a metal file. How can I tell what it might be?
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