FMF - Friends of Minerals Forum, discussion and message board

[Roger Warin]

Hi Lluis, Mike List.
I believe we think the same but we use different words to say. It is a fact that organic chemistry is a tumor in inorganic chemistry, biochemistry, however, is also an extraordinary tumor in organic chemistry.
People do not easily accept that oil can have two origins, a biotic and an abiotic one, directly produced by the planet without going through the living world.
Again, it is useful to look at a primitive mineral world, where life never existed, asteroids, whose messengers are meteorites.
They found ammonia, produced by chemical processes in some stony parent bodies (asteroids). There are also a lot of nitrogenous organic compounds and of course hundreds of thousands of "identified" organic molecules by their exact molecular weight.
When water is present (and there's always when you're far enough away from the Sun), reactions occur as on Earth. But there is another important type of reactions largely promoted in sidereal space, it is the radical processes.
Roger.

[cascaillou]

in my understanding, what allows an organic compound to be classified as a mineral is that there were natural occurences of non-biogenic formation of this compound.

So that would exlude the sugar crystal from sugar canes, as sugar was never found naturally occuring from non-biogenic processes.

On the other hand whewellite can form naturally either from biogenic processes (renal calculus) or non-biogenic processes (hydrothermal formation, or hypergene occurence in coal mines). My understanding is that it shouldn't be regarded as a mineral in the first case, but it is in the later.


Another curious point of minerals classification is about native mercury. Considering that minerals must be solids, if we break the rule for a liquid element, why not break it too for a gaseous element such as dioxygen, I mean why not consider both mercury and dioxygen as minerals of the native element class? I first assumed this was a purely pragmatic choice (I mean so to gather all metal ores together within the classification), considering that historically the origin of mineralogy lies in mining of ressources, that would make sense. But then I realized that there might be a more scientific explanation: mercury, at least in some locations of our planet, would occur as a crystallised solid. Indeed, ice is also considered a mineral (despite it would turn to a liquid in most places). While that is not the case for oxygen which would never naturally occur as a solid anywhere on earth.

However this interpretation raises a question about dry ice (that is frozen carbon dioxide). Indeed, the lower recorded temperature on earth was -89,20°C and at this temperature CO2 must have occured as a crystallised solid. Should it be added to mineral classifications (oxide class)?

This being said, if you leave earth away, other gasses might be found naturally occuring as crystallised solids (but then that's extraterrestrial mineralogy).

What's you opinion on this point of classification?

[Mark Ost]

It is easy to get caught up in these discussions of the minutiae of classification systems and definitions but perhaps the best way to approach these seeming problems is to remember that we have to draw the line somewhere, however imperfect it may be, in order to bring some organization and progress to a subject. Perhaps the best parallel I have was when I was in undergraduate school, approaching the end in my senior year. I asked a professor, fully aware of how really little I had learned so far, how we could make any statement, knowing how tenuous our knowledge was (this is called silopism in philosophy) . He had the most direct answer "well they don't give degrees for saying nothing" !

[cascaillou]

Indeed I agree that classifications are virtual abitrary lines we draw for more convenience when dealing with a subject.

But considering that collectors are obsessional by nature, let's not deny the masochistic pleasure that lies in debating a virtual -thus unsolvable- question so to feed our obsession into a vicious circle hahahahaha