FMF - Friends of Minerals Forum, discussion and message board

[Cascavel1]

Hello all,

I'm pretty new to the FMF boards but not to mineral collecting. I've been reading some of the great posts on here for a while and decided it was time to post a thread and ask a few questions. It seems there are some really knowledgeable people on here.

Here is a specimen from my personal collection of milpillas minerals. I've been a big fan ever since saw my first piece back in 2009.
I am just curious if any of you have seen specimens from this locality with this type of lite green malachite cementing together larger chunks of azurite crystals and malachite pseudomorphs? I have one other piece that has a vein of this lite colored malachite (at least that's what I think it is) running through a small crack across the piece.
In this piece the thing that amazes me is the two small crystals that project out the front and are held by this material. I have over 700 specimens from this mine but this one is by far the most unique IMO.

[Cascavel1]

Here is one more photo of the two little floater azurites held on by this green malachite(?) cement.

[Cascavel1]

I re read the post and I think I was unclear that I actually had a question. I am trying to determine if that lite green stuff is actually malachite or some other mineral??

[Peter Megaw]

Looks to me like it needs more analysis...

[marvsT/Nminerals]

Perhaps the teal colored mineral is chrysocolla. There is a photo on mindat.org (Photo ID: 145140) of azurite from the Milpillas Mine with what is probably chrysocolla and another copper silicate, plancheite.

[lluis]

Good evening

I think like marvsT, looks like crisocolla to my eyes
But as Peter said, without an analysis, all are guesses (more or less educated)

With best wishes

Lluís

[Cascavel1]

Thanks for the input. A friend also thought I might be CU sulfate of some sort. That's the great thing about the material from this locality. You never know what accessory minerals you might see.

[Peter Megaw]

Shattuckite and plancheite have both been indentified at Milpillas and their colors seem closer to this than chrysocolla. It is also possible that this is a new species for Milpillas, so it looks worth investigation.

I am not clear from the photos whether the species in question is on top of the pseudos or below?

[Cascavel1]

The species I am questioning lays on top and in between the pseudos and also serves as an attachment point for the two nice azurite crystals sticking out of the front of this piece.

Here is the only other piece I have which exhibits this same species. It fills the crack in the host rock on which the azurite crystals sit. The crack goes all the way around the back and this new mineral fills it the whole way around.

[Peter Megaw]

In Mexico last week I was offered a small lot of Milpillas material with two pieces showing remarkably similar looking teal colored stuff... so I took the opportunity to try to solve the mystery.

Unfortunately, it was easy to do as it was immediately apparent that the specimens were assembled fakes with ground up malachite mixed into the glue to make that wierd teal colored filling. Not sure if it's Elmer's or some more chemically based glue, but I would guess that swabbing the "malachite" with a Q-tip soaked in either water, alcohol or acetone will instantly impart a green color to the cotton. I'd follow that water-alcohol-acetone progression to eliminate the most obvious glues first and minimize exposure to acetone.

I actually considered buying one sample to extract a decent component but the seller did not want to admit it was a fake and held out for a "real" price.

Looking at these pictures it looks like several pieces were cobbled together with this stuff, so you might be able to disaggregate it and rescue a bit or two

Caveat emptor...again!

[Cascavel1]

What do u think it's worth in parts? 3 main pieces with no visible damage plus the two little singles on front.

[gemlover]

This forum does not do values.

john

[Peter Megaw]

Echo John: Its only value now is as a fake....although there are some fake collectors out there (double entendre intended) most would argue its value is very low, so the parts might be worth more than the whole. I guess i'd take a hard look at each part and see how it might stand on its own

[Cascavel1]

Thanks guys. Sorry I asked about values.

[Pierre Joubert]

I follow this discussion and If my understanding is correct, the lovely specimens displayed by Cascavel are fakes?! Is my assumption correct?