Mindat Logo
bannerbannerbannerbanner
Welcome!

Corundum

Posted by Olav Revheim  
Corundum
August 29, 2011 04:39PM
    
This Article is Under Construction




Click here to view Best Minerals C , and here for Best Minerals A to Z and here for Fast Navigation for finished Best Minerals articles.



Can you help make this a better article? What good localities have we missed? Can you supply pictures of better specimens than those we show here? Can you give us more and better information about the specimens from these localities? Can you supply better geological or historical information on these localities?



Corundum
Al2O3

Corundum is a common and attractive mineral that are or has been mined as a gemstone or as an industrial product at various localities around the world. The corundum article is therefore split into a multiple articles, one for each continent as follows:

Corundum main article
Corundum Africa
Corundum Americas
Corundum Asia
Corundum Australia
Corundum Europe and Russia

As of now, only the Corundum Americas has reached the "the first draft" level.

I did for a brief moment consider to split corundum articles into separate entries for corundum, sapphire and ruby, but since it is difficult to define the border line between gemmy/non-gemmy and red/pink/violet I considered political borders as less controversial, at least in this forum.


In this introduction I plan to add information on corundum as a mineral, its varieties ( ruby / sapphire), its opccurance, value, treatments and fakes. I also plan say something on the largest and most famous as well as some tentative estimates on value.This will be done before the article enters the "first draft" level.

I would appreciate feed-back and input from everyone on
- The format and content on the text already added
- other locations that should be included in the final text
- photos of better crystals than those already included in the article
- Any other info that may be relevant








Corundum
UK
Scotland, Outer Hebrides, Isle of Lewis, Loch Roag





Click here to view Best Minerals C , and here for Best Minerals A to Z and here for Fast Navigation for finished Best Minerals articles.



Edited 40 time(s). Last edit at 09/12/2012 09:00AM by Olav Revheim.
avatar Re: Corundum
August 30, 2011 12:11AM
Olav,
Congratulations for getting started on the Best Minerals article for Corundum. You have a long road ahead of you, but you have made a very fine start. Wonderful explanatory text. I am not sure why I didn't know the marble from the Taj came from there, but I didn't. You may want to develop some introductory text about corundum in general to stat the article with. I usually do that at the start, because as I work on the article things keep popping into my head that I should add to the introductory text and I find it makes for a better over all article. During the construction of big articles I sort of use the introductory text as a kind of note pad. By the time I have more or less finished the article I go back and work over the introductory text one final time. Also when people read you incomplete introductory text, they often feel that you have missed something and will tell you so and I think this is a good think because it promotes the involvement of mindat regulars. And some times you can use the opportunity to ask them questions and once in a while you can fine someone interested enough and with enough knowledge to take on the challenge of writing some best minerals articles. Involvement is good, but participation is far better. Now your other job while you are writing this article is to find two more people that know as much or more than you do and get them involved in writing some more Best Minerals articles.

I have been thinking about some standard things that we should include in all the introductory sections to each Best Mineral article. One of the things I think we should include (with a date reference) is the current number of localities for the mineral on mindat. I think we should indicate what knowledgeable people feel are the best localities and the size of the largest crystal. Can you think of other things we should include? When we have more or less gotten a list of these things together, Ill make alterations in the authors instructions for the project.
Rock

Rock Currier
Crystals not pistols.



Edited 1 time(s). Last edit at 08/30/2011 12:29AM by Rock Currier.
Re: Corundum
August 31, 2011 07:43PM
    
Thanks for your encouragement Rock :)

I have been thinking on your question on the topics to include in the introductory text. I also checked the introductions to to some of the articles I have done and the content is all over the place, so I might not be a good person to ask in this respect. I think that the question really is: " What is the minimum information about this particular mineral that will be so interesting to know that we would expect someone to put it down in writing?".

I think that will differ between variuos minerals. Corundum is a more interesting mineral for more people than parvomanganotremolite will ever be. As a minimum I think:
- Geological environment
- Largest and most attractive crystals
- Selection criteria for selecting entries for the article may be of interest.
- I've been giving the idea of including the number of Mindat entries some thought, and I have on some occasions included this number, and I am not sure whether it makes sense to include this information or not. Obviously, including the number of localities will give an indication on both rarity and attractiveness of a given mineral. On the other hand, while working with the amphiboles, I have found that the number of entries in Mindat can be rather unreliable in terms of properly referenced locations. In particular for rare minerals that are difficult to identify and for some common, but unattractive rock-forming minerals the number of locations entered in Mindat can tend to be somewhat misguiding. Maybe more approximate numbers like "less than 10", less than 100", or "more than 10.000" can be used?

In addition I think that some information can be included if applicable, such as
- relationsship to other minerals ( garnet group etc.)
- areas of use ( galena as lead and silver ore)
- Retail price segment for top specimens?
- Any significant historical importance ( ie. gadolinite being the source of 7 new elements)
- Any particularily interesting or famous specimens ( i.e the cullinan diamond)
- Fakes and synthetic (i.e gold)
- Artificial treatments to enhance specimens ( i.e radiation of smokey quartz)
- Any particular requirements for storage ( i.e realgar and light)
- any varieties

I think it will be difficult to make the complete list "mandantory", as it for instanse may be difficult to find a "particularily interesting or famous" hastingsite specimen.

I have personally come to include references to each entry whereever I can find one, as I think this will make the text easier to verify.

Olav
avatar Re: Corundum
September 02, 2011 01:14AM
Olav, All those things you suggest are good and perhaps others reading this thread may be able to suggest other topics that we might usefully address in our introductory remarks for each best minerals article. I don't think we should require any "must include" items, but I think it would be useful to post the list in the authors instructions, and ask that they be kept in mine when writing or rewriting the introductions. I know that if I had such a list, that my introductions would have been much stronger.

So anyone reading this thread: What other topics to the best minerals articles should we also cover in our introductions. We will be glad to hear from you.


We will let this sit a week or two, probably till after the Denver show to see if there are any further suggestions and then Ill write them up into a list of bullet points and place them in the authors instructions so we can keep them handy to bump our memories when we are writing the introductions.

Yes, I know what you mean about the number of localities for some minerals not being very useful. I think that nomenclature changes make quoting the number of localities on Mindat sort of meaningless for many of the minerals involved like the micas, amphaboles, pyroxines etc but I think it would certainly be interesting to most to know how many localities for which corundum is listed. Do we have any way to estimate how many corundum localities produce rubies or blue sapphires for instance? Probably there is no meaningful way to do that, but probably a paragraph on the controversy between just what a ruby is verses pink sapphire might be good to include.

Rock Currier
Crystals not pistols.
Re: Corundum
October 21, 2011 09:21PM
    
I am slowly moving forward with the "best minerals" article for corundum.

Most of the content in the individual entries are gathered from literature available on the web, and I would very much appreciate anecdotes or stories from people that has been to some of these places, or seen larger and/or better specimens in collections or museums so that I can get a more "personal touch" on the article.

I always appreciate corrections and suggestions on the text. I am also fully aware that I have barely started this article and that there are a lot of good locations I have not yet started to investigate. Suggestions for locations to add to the article is also very welcome.

(:P)

Olav
avatar Re: Corundum
October 28, 2011 10:59PM
    
There is an obscure locality on the Outer Hebrides which produced a small amount of rather large gem quality sapphires:

[www.mindat.org]

There is a photo of a sharp, very deep blue 4 cm crystal on matrix on page 103 of the book by Livingstone [Livingstone, A. (2002): Minerals of Scotland - Past and Present. NMS Publishing Ltd., 212 pp.].

Peter,

Thank you very much for pointing out this location for me. If not I am afraid that I wouldn't have included it.

Thanks

Olav




Edited 1 time(s). Last edit at 10/29/2011 12:10PM by Olav Revheim.
avatar Re: Corundum
October 28, 2011 11:52PM
    
I am glad PA corundum was mentioned, not many folks acknowledge it.
-Rowan

Rowan,

Thanks. I have found quite a lot of late 19th and early 20th century litterature on mineral locations and descriptive geology from Pennsylvania. It is really interesting stuff. I am convinced that some great stuff are hidden away in the basements of various museums in the area.

From what I understand, most of the corundum mined at the Corundum Hill, Unionville, PA was massive without any pronounced crystal shapes, and I have considered to take this entry out of the article. Do you know anything on how big/good the crystals from here could get?

Thanks

Olav


I think they are all small and rough, and like you mentioned, it was mostly massive.



Edited 2 time(s). Last edit at 10/30/2011 01:45PM by Rowan Lytle.
Re: Corundum
October 29, 2011 01:38AM
    
Olav,

I reviewed the photos and have these to offer from my collection which are already on Mindat.

Corundum (pink-purple), Warwick, New York, USA 3cm by 4cm.

©

Corundum (blue), Shimersville, Lehigh County, Pennsylvania, USA, 3.5cm by 5cm.

© Joseph Polityka

Corundum (ruby), Khit Ostrov, Northern Karelia, Northern Region, Russia. 4cm by 5.5cm.

© Renee Teresa Polityka

Best wishes,

Joe


Joe,

Thanks. Do you happen to have any information on the New York locality, on how good/abundant the corundum from there can get? Is it a locality that still produces specimens?

I have included the Shimersville specimen in the article, and I haven't even started on the Russian locations yet.

Thanks

Olav




Edited 2 time(s). Last edit at 10/29/2011 12:32PM by Olav Revheim.
avatar Re: Corundum
October 29, 2011 02:34AM
    
Olav,

A locality that has produced tons of rubies, and still is, was not listed, Mysore District, Karnataka, India (Mindat.org). Rock has gone through tons of it at his company and not that I want to be a snitch but I think I may remember him going there. Maybe he can add a little write-up to his short list of other Mindat duties (:P)

Bill

Bill,

Thank you for your input. I will definately add the Mysore district to the article . There is a lot of good locations that I still haven't started to look into. This is one of them

Thanks

Olav




Edited 1 time(s). Last edit at 10/29/2011 12:31PM by Olav Revheim.
Re: Corundum
October 29, 2011 12:39PM
    
Thanks for your input. I have responded individually into each post. Hope you don't mind.

smileys with beer

Olav
Re: Corundum
October 29, 2011 02:40PM
Dear Olav, this is excellent work. One question - one of the photos listed for Afghanistan (Rob Lavinsky) appears to be identical to one listed for Vietnam (also Lavinsky)! Perhaps you could ask him about this? Thanks for all your work. Becky

Thank you Becky.
I am amazed that you were able to see that the two photos was of the same specimen. I contacted Timoth Blackwood and he corrected this immediately.

Olav




Edited 1 time(s). Last edit at 10/30/2011 06:30AM by Olav Revheim.
avatar Re: Corundum
October 29, 2011 03:11PM
    
Olav:

Don't forget the very important gem corundum deposits of Burma, Viet nam, and Australia! That, plus there are several very important deposits in Montana that are not mentioned here: the Yogo Gulch deposit; the El Dorado Bar near York; Montana, the Gem Mountain near Philipsburg, Montana; the corundum from the Virginia City dredge tailings (asteriated masses to 650 grams and more!), plus the famous star corundum deposit on the Sweetwater Road east of Dillon, Montana.

Chris


Chris.

Thank you so much for pointing out the Montana locations. There are very few photos from there on Mindat and I could easily have missed some of them. Burma, Vietnam, Australia, Russia etc. is still pending work.....

Thanks

Olav


William C. (CHRIS) van Laer: "I'm using the chicken to measure it..."



Edited 1 time(s). Last edit at 10/30/2011 06:33AM by Olav Revheim.
avatar Re: Corundum
October 29, 2011 10:19PM
Olaf, well done, though I noted a native copper amongst the corundums!

Regards,
Ralph
avatar Re: Corundum
October 30, 2011 12:09AM
    
Hi Ralph,

The sudden presence of the native copper photo is my fault. Olav contacted me concerning two photos of the same corundum specimen showing two different locations. Photo-22974 had been a ruby labeled as being from Jegdalek, Afghanistan. Photo-180102 is, of course, corundum (var: ruby). The locality for photo-180102 in the report above should be Jegdalek, Afghanistan. I have corrected the locality on the photo in the gallery. In correcting the locality information, I changed the photo for 22974 to a nice copper specimen to eliminate the duplication of the ruby. I'm sorry for the confusion. :(

Best wishes,
Tim Blackwood

Tim,

Thank you so much for your swift response on my inquiry. I'm impressed.

Olav




Edited 1 time(s). Last edit at 10/30/2011 06:36AM by Olav Revheim.
Re: Corundum
October 30, 2011 04:49AM
Olav,
I miss a really uncommon locality of corundum (http://www.mindat.org/loc-10156.html) in your Article. It is Amstall in Austria where corundum occours in graphite together with a Vanadium bearing Mica, Vanadium bearing Dravite-Olenite, Sillimanite, Rutile and Pyrite.
Martin

Martin,

Thank you for addressing this location. I will add it eventually. I started this article by picking some of the good locations rather randomly, but right now I'm focusing on the US and Madagascar. I will add more locations, including Amstall, in time

Olav




Edited 1 time(s). Last edit at 10/30/2011 06:40AM by Olav Revheim.
Re: Corundum
October 30, 2011 06:43AM
    
I would like to thank all of those commenting on this article. I appreciate the input as it improves the quality of this work tremendously.

Thanks

Olav
avatar Re: Corundum
October 30, 2011 06:39PM
    
Hi Olav,

You're very welcome. I try to take care of inquiries as soon as possible. I'm glad I was able to be of help. :)

Best wishes,
Tim
Author:

Your Email:


Subject:


Attachments:
  • Valid attachments: jpg, gif, png, pdf
  • No file can be larger than 1000 KB
  • 3 more file(s) can be attached to this message

Spam prevention:
Please, enter the code that you see below in the input field. This is for blocking bots that try to post this form automatically. If the code is hard to read, then just try to guess it right. If you enter the wrong code, a new image is created and you get another chance to enter it right.
CAPTCHA
Message:
Mineral and/or Locality  
Search Google  
Copyright © Jolyon Ralph and Ida Chau 1993-2014. Site Map. Locality, mineral & photograph data are the copyright of the individuals who submitted them. Site hosted & developed by Jolyon Ralph. Mindat.org is an online information resource dedicated to providing free mineralogical information to all. Mindat relies on the contributions of thousands of members and supporters. Mindat does not offer minerals for sale. If you would like to add information to improve the quality of our database, then click here to register.
Current server date and time: October 25, 2014 11:59:11
Mineral and Locality Search
Mineral:
and/or Locality:
Options
Fade toolbar when not in focusFix toolbar to bottom of page
Hide Social Media Links
Slideshow frame delay seconds