Azurite and Malachite

Does "primary" malachite ever occur with azurite?


TTFN

"Primary" malachite????

Yes Steve. Often botryoidal malachite occurs with azurite crystals that have grown after the malachite. I don't believe azurite and malachite would crystallize contemporaneously though...need to check stability diagrams.

Often malchite and azurite crystallize repeatedly during the paragenesis as the conditions within the system vary.

Cheers,
Ian

Maybe he means "non-pseudomorphous-non-acicular", like the equant emerald green xl from Congo.
Steve

Ian,

Thanks.

My perception of "primary" malachite(which is terminology I gleened from "this website",is malachite which has not altered from azurite, or any other mineral.

TTFN

PS I'm sure I'll be told I'm wrong, as negativity, and not positivity(education) are the norm for this site.

I understood the term "primary malachite" as it was meant - I thought it was a pretty universal term for equant crystalline malachite.

Jolyon

I'm never visiting this website ever again. You're all a bunch of dilettantes(except Mr Peck) who can't agree on anything. J. Betts is right.

YCAGFYTTFNDILIGAS

Gentlemen,
Thank you for this thread. I have had a similar question and my question was answered. It is always refreshing to have your professional and interesting discussion and interaction. I happen to love copper minerals and some of you have been kind enough to send me some samples and I wondered about the mineral assemblage in the azurite and malachite sample. I do not share the sentiments of Mr. Kittleson and thank you again.

Good question Steve, None of my primary Malachite specimens have Azurite with them. I don't know the answer.

Don't give up on the site yet, sometimes you just need to grit your teeth and ignore some comments. No-matter where you go in this world there's always one or two superior beings.

Mark R.,

Now, I'm going to be a hypocrite, for responding. "So it goes"(anyone know what novel that phrase comes from?). My statement wasn't out of arrogance(probably 95+% of the respondants to this website are more knowledgeable than I), I just get tired of being faulted for trying to understand the "vague and differing" definitions given by the contributors.

Linda, your? if the same as mine, was not answered.

Mobius strip.


Goodbye all.

Steve,
Yes, primary malachite does occur with azurite, although I doubt that they crstallized contemporaneously. Primary malachite can occur as distinct singular crystals, as Mark and perhaps Jolyon were reffering to, and as crusts, often banded. Primary malachite also occurs as accicular crystals.

Although they do occur together, they may not be both stable at the same time, but dissolution of either mineral during precipitation of the other may be kinetically "slow" and therefore preservation of both minerals is accoplished. This theory to explain the occurence of primary malachite with azurite I do not know for sure though.

Cheers.
Ian

"... don't believe azurite and malachite would crystallize contemporaneously though...need to check stability diagrams."

They can, of course, if the conditions are those of a line separating the two stability fields.

Uwe, is there another way of saying this?
"They can, of course, if the conditions are those of a line separating the two stability fields".



Edited 1 time(s). Last edit at 05/06/2008 07:06AM by Mark Rheinberger.

The "lines" separating the "fields" in a phase diagram represent the conditions in which the phases represented by the adjacent fields are in thermodynamic equilibrium.

Sorry, but there is no way to explain this more simply. Getting used to phase diagrams requires some physico-chemical background. If you want to learn more about this topic, a good point to start with is an undergraduate physical chemistry textbook.



Edited 1 time(s). Last edit at 05/06/2008 08:43AM by Peter Haas.

Mark,

In a phase diagram, fields represent conditions when minerals are stable to crystallize or exist. These conditions could be all sorts of things with axes defined commonly by temperature, pressure, eH, Ph, ion activity etc... If two fields are adjacent to each other and condition are so that they correspond exactly to the line seperating the two fields, then both minerals can crystallized together. Although theoretically this is true, if it really occurs in nature is another question. That line is infintesimally small and very finite. Reaction kinetics come into play and whether or not either, both or netiher minerals actually crystallize is not so simple.

Hope this helps.

Ian

Thanks Ian and Peter, I do have some understanding of what is required for minerals to crystallise out of solution, but I was not that familar with the terminology. I do wish I had a better grip on chemisty.
Mark