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abundance of a mineral and crystals size range

Posted by cascaillou  
abundance of a mineral and crystals size range
November 24, 2011 02:18AM
I don't know if that could be done practically, but it would be interesting to know what is roughly the size range that can be expected for the crystals of a given specy.
I mean like 'mostly sub-millimetric', 'usually millimetric', 'unfrequently centimetric, or 'often centimetric' (based on previously reported finds).
To answer this question I usually check the photo gallery, but for some lesser-known minerals the photographic content is too thin to judge of what would have been found around the world.

Another interesting feature would be mentionning the relative abundance of the mineral.
I mean like 'very abundant', 'abundant', 'locally abundant', 'frequent', 'rather rare', 'rare', 'very rare'
Abundance is not only a matter of worldwide occurences, but also a matter how concentrated the mineral is in these regions.


I'm mainly suggesting these two features because when you search mindat, there are just too many minerals, and I often find myself wondering how 'significant' is a given mineral that I had never heard about before, and I guess I'm not the only one feeling a bit lost.



Edited 9 time(s). Last edit at 11/26/2011 10:12PM by el cascaillou.
avatar Re: abundance of a mineral and crystals size range
November 24, 2011 02:58PM
    
If you click on the "i" icon in front of a mineral (ion the list for a locality), you will bring up a detail record for the mineral at the locality. It has information on the following:
5 Methods
6 Crystal habits
7 Colours
8 Fluorescence
9 Quality for species at this locality
10 Rarity at site
11 Comments
12 Reference

Size tends to be incorporated in "Habits"
Unfortunately less than 1% of the entries have any of this information filled in.
Re: abundance of a mineral and crystals size range
November 24, 2011 03:43PM
    
Generally you can get a pretty good idea of the abundance or rarity by looking at the number of occurrences in the world as noted on Mindat. However that does not always translate directly to availability which adds another dimension to the meaning of the words abundant or rare.
Re: abundance of a mineral and crystals size range
November 24, 2011 05:07PM
sure, but market availability is a different story.
Re: abundance of a mineral and crystals size range
November 24, 2011 08:17PM
    
Market availability is beyond the capability of any database like Mindat. Availability fluctuates and thus there will always be some data that is out of date. As such, any information would likely be misleading ( and could be manipulated) which could result in some angry people. There is really not much upside to Mindat attempting such a task that I can see. Of course Jolyon may have a different opinion.
Re: abundance of a mineral and crystals size range
November 24, 2011 09:13PM
agreed, market avaibility is irrelevant here and would be meaningless mineralogically speaking.

I'm only suggesting a mention of natural abundance of a given mineral, and crystals size range for a given mineral.

For instance, quartz: 'very abundant', crystals 'often centimetric'.

That would be enough to allow a mineral collector to get a good idea of what he can expect from a given mineral.

I would add that this could also facilitate the use of the mindat search engine by allowing one to eliminate irrelevant minerals from a search.



Edited 8 time(s). Last edit at 11/24/2011 09:44PM by el cascaillou.
Re: abundance of a mineral and crystals size range
November 25, 2011 03:50AM
Any database built by volunteers is only going to contain the information that the volunteers found interesting enough to add. As David pointed out, less than 1% of contributions made use of the functionality we already have to add some (vague) information on rarity and quality at a given site.

You can get some hints by seeing how many photos have been added for any given mineral at a site. With close to a half million photos on Mindat, growing rapidly, the selection is slowly acquiring some statistical significance. A mineral on a locality list NOT depicted on any photo would seem to indicate that is is either uninteresting or not readily available (with millions of exceptions to be sure ;)



Edited 1 time(s). Last edit at 11/25/2011 03:51AM by Alfredo Petrov.
avatar Re: abundance of a mineral and crystals size range
November 25, 2011 11:25AM
    
"I'm only suggesting a mention of natural abundance of a given mineral, and crystals size range for a given mineral.

For instance, quartz: 'very abundant', crystals 'often centimetric'.

That would be enough to allow a mineral collector to get a good idea of what he can expect from a given mineral."

That is sort of what the "Best Minerals" does.
Re: abundance of a mineral and crystals size range
November 25, 2011 12:49PM
    
Another problem with this sort of information is that rarity or abundance often varies depending on where mining is taking place and sometimes even who is looking at the rocks. I've been to places where I found lots of say mineral X but most people find nothing, is it rare? Not to me. Also while mining is taking place in a certain area ( say the oxidized zone) a particular mineral may be common and then when mining progresses to a different area never be seen again, and rarely is anyone in a position to do a quantitative mineralogical assessment of a particular deposit. As for crystal size, that also changes as new occurrences are discovered and not everyone contributes to Mindat so the information will always be incomplete.
avatar Re: abundance of a mineral and crystals size range
November 25, 2011 01:34PM
I think such a system is going to end up with more frustration ("But, it said 1cm crystals were common at this site, and I can't find any more than 5mm!") than benefits.
Re: abundance of a mineral and crystals size range
November 26, 2011 03:03AM
Quote
"But, it said 1cm crystals were common at this site, and I can't find any more than 5mm!

well I was thinking global worldwide, not local.

when I said quartz 'very abundant' crystals 'often centimetric', that was thinking worldwide. This is what a mineral collector can expect from quartz in a general way.

I actually own a mineralogy book that gives that kind of global estimate for each mineral, which I find useful.
avatar Re: abundance of a mineral and crystals size range
November 26, 2011 02:51PM
El,
What is the book you have that gives such estimates? Do you know the Handbook of Mineralogy that has for each mineral listed the maximum crystal size known? We try and incorporate these and in some rare instances larger sizes when they are known in the introduction of each mineral in the Best Minerals articles. It would be nice to incorporate in this section a global estimate of its abundance.

Rock Currier
Crystals not pistols.
avatar Re: abundance of a mineral and crystals size range
November 26, 2011 03:02PM
    
Probably Stefan Weiss - Das grosse Lapis Mineralienverzeichnis.
Re: abundance of a mineral and crystals size range
November 26, 2011 04:32PM
In the book mentioned by David, you find indicated with each mineral:
for the dimensions 4 possibilities:
only microscopic
fine-grained or microcristals
crystals smaller than 3 mm
crystals larger than 3 mm

for the abundance:
common
known from a number of localities and there sometimes rather abundant, but all together rather limited
rare , only known from few places or only a limited number of specimens (or from one locality, where it is relatively abundant)
very rare, only a few specimens known
Re: abundance of a mineral and crystals size range
November 26, 2011 04:51PM
the book I mentionned only gives an estimation of abundance of occurence worldwide, in the terms I mentionned in my first post. It is a book written in french. 'la grande encyclopedie des mineraux', edition Grund, by Rudolf Duda.

I had never noticed that in handbookofmineralogy.org (is that the same book?) , thanks for pointing it to me!



Edited 6 time(s). Last edit at 11/26/2011 10:09PM by el cascaillou.
avatar Re: abundance of a mineral and crystals size range
November 27, 2011 01:58AM
Yes, that is the book. At the very top of each page/mineral in the Crystal Data: section there is listed the largest size known for crystals, which in a very high percentage of cases if correct at least as far as I have been able to determine.

Rock Currier
Crystals not pistols.
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