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Corundum
Geology.com ^ | 9/19/2014 | Hobart King

Posted on 09/19/2014 7:39:28 PM PDT by JimSEA

Corundum is a rock-forming mineral that is found in igneous, metamorphic, and sedimentary rocks. It is an aluminum oxide with a chemical composition of Al2O3 and a hexagonal crystal structure.

The mineral is widely known for its extreme hardness and for the fact that it is sometimes found as beautiful transparent crystals in many different colors. The extreme hardness makes corundum an excellent abrasive, and when that hardness is found in beautiful crystals, you have the perfect material for cutting gemstones.

(Excerpt) Read more at geology.com ...


TOPICS: Science
KEYWORDS: ruby; sapphire
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There is mostly synthetic corundum in industrial use and ruby lasers can only use synthetic rubies. However, natural formation are fascinating.
1 posted on 09/19/2014 7:39:28 PM PDT by JimSEA
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To: JimSEA
And who doesn't love the Lake Superior agates.


2 posted on 09/19/2014 7:45:30 PM PDT by cripplecreek ("Moderates" are lying manipulative bottom feeding scum.)
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To: cripplecreek

That is just lying around, there?

Wow!

/total rock hound


3 posted on 09/19/2014 7:47:23 PM PDT by Salamander (People will stare. Make it worth their while.)
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To: cripplecreek

Beautiful.


4 posted on 09/19/2014 7:47:37 PM PDT by BenLurkin (This is not a statement of fact. It is either opinion or satire; or both.)
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To: Salamander

Yeah, they’re pretty common all around lake superior but you have to be careful where you pick them up due to various federal state and local laws.


5 posted on 09/19/2014 7:51:24 PM PDT by cripplecreek ("Moderates" are lying manipulative bottom feeding scum.)
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To: JimSEA

6 posted on 09/19/2014 7:52:43 PM PDT by HangnJudge
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To: JimSEA

If Corundum is over 50% red it is Ruby... all other color are Sapphire. Fine Ruby is my favorite gem.


7 posted on 09/19/2014 7:53:20 PM PDT by DocRock (All they that TAKE the sword shall perish with the sword. Matthew 26:52 Gun grabbers beware.)
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To: cripplecreek

you rock!


8 posted on 09/19/2014 7:54:23 PM PDT by smokingfrog ( sleep with one eye open (<o> ---)
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To: cripplecreek

Those are spectacular.


9 posted on 09/19/2014 7:56:38 PM PDT by JimSEA
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To: HangnJudge

I know what that means! I didn’t learn this latin in private school though. Mad Michael Savage (himself!) translated this for me and other radio listeners years ago. It means “Don’t Let The Bastards Grind You Down!”


10 posted on 09/19/2014 7:57:26 PM PDT by lee martell
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To: JimSEA

Petoskey stones are pretty cool as well. They’re actually fossil coral.


11 posted on 09/19/2014 7:58:48 PM PDT by cripplecreek ("Moderates" are lying manipulative bottom feeding scum.)
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To: cripplecreek
Custom made knife with Michigan Petoskey stone inlay on the grip.


12 posted on 09/19/2014 8:04:29 PM PDT by cripplecreek ("Moderates" are lying manipulative bottom feeding scum.)
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To: DocRock

I’ve been to one played out mine in marble near Phrae, Thailand. My wife loves ruby and sapphire as well. The Thais craft their local designs in gold (24 Carat). They have some spectacular jewelry.


13 posted on 09/19/2014 8:06:07 PM PDT by JimSEA
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To: cripplecreek

That’s nice work. There can’t be many of those around.


14 posted on 09/19/2014 8:07:46 PM PDT by JimSEA
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To: cripplecreek

I’d rather have that than jade with no story to tell.


15 posted on 09/19/2014 8:09:25 PM PDT by JimSEA
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To: JimSEA

Sounds like the guy is a friend of the owner of Spyderco knives. He’s in SC but picked up the stone in Michigan and had it done so its a one of a kind job.

http://paulberetta.com/index.htm

He has lots of knives.

http://paulberetta.com/kiwimania/index.html


16 posted on 09/19/2014 8:11:07 PM PDT by cripplecreek ("Moderates" are lying manipulative bottom feeding scum.)
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To: cripplecreek

“...but you have to be careful where you pick them up due to various federal state and local laws.”

I try to follow all of the rules, but seeing such a bunch of pretty rocks, and perhaps not knowing exactly what the rules were, would I grab just one or not? Quite the condudrum.


17 posted on 09/19/2014 8:14:51 PM PDT by 21twelve (http://www.freerepublic.com/focus/f-news/2185147/posts 2013 is 1933 REBORN)
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To: cripplecreek
“...but you have to be careful where you pick them up due to various federal state and local laws.”

I try to follow all of the rules, but seeing such a bunch of pretty rocks, and perhaps not knowing exactly what the rules were, would I grab just one or not? Quite the conundrum.

18 posted on 09/19/2014 8:15:06 PM PDT by 21twelve (http://www.freerepublic.com/focus/f-news/2185147/posts 2013 is 1933 REBORN)
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To: lee martell

The Latin saying is also rendered as “Ne illegitimi non te carborundum”

(Double negative is correct in Latin, plus the second person singular as direct object).

“Semper ubi sub ubi”

;^)


19 posted on 09/19/2014 8:27:28 PM PDT by elcid1970 ("In the modern world, Muslims are living fossils.")
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To: 21twelve

A conundrum over corundum - quite understandable.


20 posted on 09/19/2014 8:30:21 PM PDT by cyn (Benghazi)
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