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Fiebre Verde · Joined: 11 Sep 2013 Posts: 946 Location: Paris Area

Calcite crystals show deep striations.
Striated calcite is not uncommon in the La Pita district but this specimen exhibits a pattern which looks more like a series of ridges than ordinary striation.
I would love to hear an explanation on this - growth pattern? else?

yowanni · Posted: Dec 16, 2015 02:47 Post subject: Re: Collection of Fiebre Verde

Hello Fiebre Verde,
It seems like an etching-dissolution pattern.

Fiebre Verde · Joined: 11 Sep 2013 Posts: 946 Location: Paris Area

Jordi Fabre · Posted: Dec 16, 2015 17:02 Post subject: Re: Collection of Fiebre Verde

It looks anthropogenic to me...

Ricardo Melendez · Joined: 21 Apr 2014 Posts: 70 Location: Estado de Mexico

I have seen calcites with that pattern after hydrochloric acid treatment.

very likely in your specimen.

minsur · Joined: 03 Feb 2015 Posts: 46

A combined process to form "interesting looking crystals" out of damaged or cleaved Calcite???
First a scratch job with a file (pocket-knife-file?) and then a short acid bath?
So much work to manufacture an average specimen, at best?

More questions than answers...

Fiebre Verde · Joined: 11 Sep 2013 Posts: 946 Location: Paris Area

Thanks Minsur, Jordi & Rocardo. Seems like we have a consensus on the origin of these strange patterns!

This does not really come as a surprise to me as emerald sculptures and carvings is an important business in Bogota. Usually the artistic emphasis is focused on the low-grade emerald material and not the surrounding crystals!

Can't remember how this specimen ended up in my collection.

Gérard

Fiebre Verde · Joined: 11 Sep 2013 Posts: 946 Location: Paris Area

A recent find from the Chivor district.
Pyrite is partly oxidized.

minsur · Joined: 03 Feb 2015 Posts: 46

Very nice indeed!
This one is certainly NOT carved;)))))

Fiebre Verde · Joined: 11 Sep 2013 Posts: 946 Location: Paris Area

Fiebre Verde · Joined: 11 Sep 2013 Posts: 946 Location: Paris Area

If the beryl prism is light-green, clean and bulky, it might then come from La Pava.
Unfortunately La Pava has a very erratic production and specimens from this location are rarely seen in the market.
The La Pava tunnel is located about 5km west of the historical Tequendama Muzo mining area.
Could not resist posting several images of this specimen!

Fiebre Verde · Joined: 11 Sep 2013 Posts: 946 Location: Paris Area

I thought I could end the year on a light note.
It's Colombian, it's a beryllium mineral but it's not a beryl...
La Marina mine is also known for producing the equally desirable pink tabular fluorapatite.
Euclase was historically produced in the Chivor mining district (mainly the Gachalá mining area).
Although La Marina is just a few kilometers off the La Pita mining district, emeralds have yet to be found.
Host rock is black shale.

Happy Christmas to all of you!

Fiebre Azul (for a change)

minsur · Joined: 03 Feb 2015 Posts: 46

Fiebre azul, why not hand over this really ugly BLUE crystal to one of these modern, state-of-the-art labs, where they will just spill over some yellow stuff to turn its awful light blue colour into a beautiful GREEN. And then, of course, trim the whole thing to a "Killer"- Thumbnail:-((((
Caso resuelto;)))

By the way, I am beginning to understand, why I see this amount of screaming fakes, even at big shows and with important dealers. You must have cornered the market for the authentic and nice specimens;)))))

Thank you so much for your interesting postings and to come to an end... felizes fiestas:)

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