January 24 Through February 4—TUCSON, ARIZONA: Annual show
Welcome to the GemologyOnline.com Forum
A non-profit Forum for the exchange of gemological ideas
It is currently Thu Mar 28, 2024 11:16 am

All times are UTC - 4 hours




Post new topic Reply to topic  [ 33 posts ]  Go to page 1, 2, 3  Next
Author Message
 Post subject: dodecahedron corundum?
PostPosted: Sun Feb 24, 2013 12:53 pm 
Offline
Established Member

Joined: Sun Feb 24, 2013 9:27 am
Posts: 11
Location: Eastern edge of the Blue Ridge Mnts. Virginia
I know that identifying gems by a picture is impossible. What I would like to know is what would be the easiest way to make sure this stone is worth paying to have it identified. I am not a rock hound or a gem collector. I took a friend and her grandson to one of those road side sluice mines in Virginia last year during vacation and found this rock. When the mine owner was identifying our rocks for us he seemed to dismiss it and move on to other rocks quite quickly. One of the employees thought it was probably Corundum. Research online hasn't helped me to much. It is an imperfect dodecahedron and quite heavy for its size.


Attachments:
dodecahedron ruby 002.jpg
dodecahedron ruby 002.jpg [ 18.25 KiB | Viewed 1565 times ]
dodecahedron ruby 003.jpg
dodecahedron ruby 003.jpg [ 23.66 KiB | Viewed 1565 times ]
Top
 Profile  
Reply with quote  
 Post subject: Re: dodecahedron corundum?
PostPosted: Sun Feb 24, 2013 1:23 pm 
Offline
Gemology Online Übergod
User avatar

Joined: Tue Aug 01, 2006 3:24 am
Posts: 4997
Location: McDonough GA
Quite right, one cannot identify a stone from a photo.

That said, it appears to be a garnet.

_________________
http://www.selectgem.com


Top
 Profile  
Reply with quote  
 Post subject: Re: dodecahedron corundum?
PostPosted: Sun Feb 24, 2013 3:33 pm 
Offline
Site Admin
User avatar

Joined: Sun Oct 16, 2005 12:22 pm
Posts: 21602
Location: San Francisco
Agreed.


Top
 Profile  
Reply with quote  
 Post subject: Re: dodecahedron corundum?
PostPosted: Sun Feb 24, 2013 3:39 pm 
Offline
Site Admin
User avatar

Joined: Fri Apr 17, 2009 3:53 pm
Posts: 2049
Location: Sweden
Agreed again :)

_________________
_____________
Conny Forsberg


Top
 Profile  
Reply with quote  
 Post subject: Re: dodecahedron corundum?
PostPosted: Sun Feb 24, 2013 4:26 pm 
Offline
Site Admin
User avatar

Joined: Fri May 12, 2006 11:24 am
Posts: 7523
Location: Rome, Italy
+ 1 8)

_________________
GemmoRaman-532 - GemmoFTIR - GemmoSphere - EXA


Top
 Profile  
Reply with quote  
 Post subject: Re: dodecahedron corundum?
PostPosted: Sun Feb 24, 2013 4:38 pm 
Offline
Established Member

Joined: Sun Feb 24, 2013 9:27 am
Posts: 11
Location: Eastern edge of the Blue Ridge Mnts. Virginia
Thanks! That information led me to Pyrope... this particular road side mine was salted with stones from Brasil.


Top
 Profile  
Reply with quote  
 Post subject: Re: dodecahedron corundum?
PostPosted: Sun Feb 24, 2013 6:47 pm 
Offline
Site Admin
User avatar

Joined: Sun Oct 16, 2005 12:22 pm
Posts: 21602
Location: San Francisco
Guy Griffin wrote:
Thanks! That information led me to Pyrope...

why?


Top
 Profile  
Reply with quote  
 Post subject: Re: dodecahedron corundum?
PostPosted: Mon Feb 25, 2013 9:45 am 
Offline
Established Member

Joined: Sun Feb 24, 2013 9:27 am
Posts: 11
Location: Eastern edge of the Blue Ridge Mnts. Virginia
Why? I knew where the stones came from (I bought a bucket salted with potential rubies) and the color of the stone. The stones came from an area that was being mined for Aluminum and Corundum for use in abrasives. It may not be Pyrope, but the other alternative based on locations and stone color would be Almandine, but then it could be natural to the area, though if that amount of garnet is on that particular farm I would think that they would be mining it for abrasives or the aluminum. The dodecahedron shape does point it toward Almandine, but either Almandine or Pyrope, if it is not to fractured it may cut into a nice conversation piece.


Top
 Profile  
Reply with quote  
 Post subject: Re: dodecahedron corundum?
PostPosted: Mon Feb 25, 2013 10:07 am 
Offline
Established Member

Joined: Sun Feb 24, 2013 9:27 am
Posts: 11
Location: Eastern edge of the Blue Ridge Mnts. Virginia
Barbra Voltaire wrote:
Guy Griffin wrote:
Thanks! That information led me to Pyrope...

why?


We were told that the particular mine was salted with stones from Brazil. They got the stones from an area that mined for abrasives. The color of the stone fits close to either Pyrope or Almandine, along with the Rhombic Dodecahedron shape. I have not found all of the answers, like do Rubies and Garnet both appear with Corundum? Using Garnet as my key word, it was easy to search out the different possibilities. The bucket that we bought was supposedly salted with potential Rubies. Well, no Rubies were found as far as I can tell, but we did find a lot of wine red garnet. The on-site gemologist suggested some of the stones we found might be rubies, but after checking the color most were way to deep wine red to be rubies. We could have them tested, but polishing the stones and wondering if they really are Rubies is more fun than knowing they aren't. Thanks again!


Top
 Profile  
Reply with quote  
 Post subject: Re: dodecahedron corundum?
PostPosted: Mon Feb 25, 2013 10:56 am 
Offline
Gold Member
User avatar

Joined: Mon Apr 16, 2007 12:05 am
Posts: 1499
Definitely looks like opaque almandine garnet. By the way, I think the 4-5 sided faces are called "kites."

You can pick up much-less-included examples of these crystals for very cheap at any gem and mineral show. I think they make for very fun and interesting paperweights.

Quote:
do Rubies and Garnet both appear with Corundum?

ruby is corundum.


Top
 Profile  
Reply with quote  
 Post subject: Re: dodecahedron corundum?
PostPosted: Mon Feb 25, 2013 8:10 pm 
Offline
Moderator
User avatar

Joined: Thu Dec 13, 2007 3:42 pm
Posts: 4091
Location: the Netherlands
Guy,

Have a close look at that crystal. Which one of the two below is it?

Attachment:
guy's corundum.jpg
guy's corundum.jpg [ 72.89 KiB | Viewed 1458 times ]


Top
 Profile  
Reply with quote  
 Post subject: Re: dodecahedron corundum?
PostPosted: Tue Feb 26, 2013 8:54 am 
Offline
Established Member

Joined: Sun Feb 24, 2013 9:27 am
Posts: 11
Location: Eastern edge of the Blue Ridge Mnts. Virginia
Tim,
It is the second one you have pictured.


Top
 Profile  
Reply with quote  
 Post subject: Re: dodecahedron corundum?
PostPosted: Wed Feb 27, 2013 9:54 am 
Offline
Moderator
User avatar

Joined: Thu Dec 13, 2007 3:42 pm
Posts: 4091
Location: the Netherlands
Right... in that case you have an hexagonal bipyramid with basal pinacoids which would probably make your crystal....

drum roll...

A bit of corundum...


Top
 Profile  
Reply with quote  
 Post subject: Re: dodecahedron corundum?
PostPosted: Wed Feb 27, 2013 11:04 am 
Offline
Site Admin
User avatar

Joined: Sun Oct 16, 2005 12:22 pm
Posts: 21602
Location: San Francisco
I think a hardness test may be in order.


Top
 Profile  
Reply with quote  
 Post subject: Re: dodecahedron corundum?
PostPosted: Wed Feb 27, 2013 11:14 am 
Offline
Established Member

Joined: Sun Feb 24, 2013 9:27 am
Posts: 11
Location: Eastern edge of the Blue Ridge Mnts. Virginia
Barbra Voltaire wrote:
I think a hardness test may be in order.

That is exactly where my mind went yesterday when I saw the pictures that Tim put up. I will find someone local that can help me with that and hopefully post the results. I did check to see if I could mark a face with a normal bench grinder, the mineral included with the crystal is soft like aluminum and melted on the facet, but I did nothing to the crystal. I don't have any diamond blades at the moment, but was wondering if I should smooth a face before trying to test the hardness?


Top
 Profile  
Reply with quote  
Display posts from previous:  Sort by  
Post new topic Reply to topic  [ 33 posts ]  Go to page 1, 2, 3  Next

All times are UTC - 4 hours


Who is online

Users browsing this forum: No registered users and 19 guests


You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot post attachments in this forum

Search for:
Jump to:  
Powered by phpBB © 2000, 2002, 2005, 2007 phpBB Group
Gemology Style ported to phpBB3 by Christian Bullock