FMF - Friends of Minerals Forum, discussion and message board

[Fiebre Verde]

Hi Bergur,
So the mystery is cracked!
There are several references describing the presence of "pearly white" allophane in both emerald belts formed as a result of alteration of albite.
Good find!
Gérard

[Bergur_E_Sigurdarson]

Some more recent additions to my collection.

A couple of months ago I found a small piece of shale matrix with some calcite and micro-quartz as well as .... faintly blue fluorites.
Being sold by one of the outside dealers on the little plaza in Bogota. He wasn't sure where it was from... but just looking at the piece I was almost sure it was Colombian.
I just had never heard of blue fluorite here.

Then later I went on a trip to the western emerald belt and in Santa Barbara, the little village north of Coscuez, a collector had a few loose pieces of blue fluorite on display. He very generously gave me one... a very complete crystal, tho without matrix.
He was very sure of it's origin, Florian, Santander.

The last of the little blues I have now is very faint, possibly from exposure to light.
Again a street vendor in Bogota, so no location, and sadly no matrix (I'm still quite convinced it's Colombian)

On my trip to the western belt I also spoke to a collector and vendor in Muzo who has a stake in a mine in Peñas Blancas (the one I spent a whole day inside) who told me that very occationally they did find blueish fluorites up there.

I have now seen not just the typical transparent with green stripe fluorites here, but a few slightly pink, some still with the green strip near the corners. A very damaged piece I could not buy that was quite intensely pink. The light blues as well as some really nice little very clear and gemmy ones.
Looking forward to exploring what else is hidden in this country :-)

[Bergur_E_Sigurdarson]

Having browsed through most of the Colombian information available on Mindat, I've become more and more interested in getting specimens of what comes out of this country.

This is one of the most recent, a light blue sapphire.

Of the very few found here, most are very damaged by river tumbling and have a satin finish. But occationally some shinier ones are found. Not sure if it's from looking further up the river area or what.

The area might have quite a bit of corundum but the main reason, it seems, for so little material to come out of it, is that there are still guerrilla and autodefensas fighting there.

[Bergur_E_Sigurdarson]

I'm back in Colombia... since the beginning of December.
Might be staying for quite some while this trip.

Already got a few nice new pieces and have my camera with me.

First off, here is an awesome elongated and twisted quartz crystal with side-growths that are almost missing two sides of the usual hexagonal shape, from Boyaca.
(most likely in the area close to Peñas Blancas... even possibly across into Santander as it's quite close by - exact locality not given by seller, Inocencio Nuñes of Muzo)

[Bergur_E_Sigurdarson]

Although I have seen pieces of greenish Calcite here in Colombia, they have not been in the classic shape.
Most have been incomplete and of a more grassy green hue and with no sign of matrix.

Recently I've seen a few that are attributed to a mine "near Otanche"
...they are clearly coming from veins in black shale and some have a bit attached to their backs, and some are nicely twinned in some way.

I wonder if they are from the Ormicol, that is situated just by the entrance to Otanche, where early this year some nice Siderite/Dolomite/Quartz/micro-Pyrite combos (and even a bit of Sphalerite) came out of?

Here are two of my samples of this "new" greenish Calcite (almost blue-green hue)

[Bergur_E_Sigurdarson]

I got this large quartz a couple of weeks ago, it has some damage (which is common here, especially when from the street sellers).
It has micro-inclusions of epidote and although an exact locality is missing, I do know it comes from Cauca-department.
The whole crystal is milky, but in a greenish-blue colour and because of it's size I'm not too bothered by the slight damage.

[Tobi]

Very impressive quartz with wonderful inclusions, I really like it :-)

[Bergur_E_Sigurdarson]

A wonderful cluster of Euclase, currently the best I own.
Displaying good colour for Vega de San Juan.

Next to no damages (haven't looked with loupe, but neither my eyes nor my macro lens see any).
A couple of internal cleavages possibly from using explosives in extraction - but fortunately the crystals remain complete.

Acquired around Newyears 2020.... from a find in the end of 2019.

[Firmo Espinar]

Hi Bergur.

Nice Euclase.

A group with more crystals than usually i´ve seen.

Regards.

[Fiebre Verde]

Blue fireworks!

[Bergur_E_Sigurdarson]

Although it's not very large and has some minor imperfections, this is one of my favourite Pyrite crystals as it has wonderfully complex faces.

[Bergur_E_Sigurdarson]

A large plate of Dolomite, with minor Calcites and specs of Pyrite, from Chivor.

Most of these get very damaged in extraction as the miners focus almost solely on finding "green" (Emerald, but of course).

Colour has hints of blue in the gray, which is rather unusual for the Eastern Belt.
All my Colombian Dolomites that are blue come from the West, except this one (altho they are a much more intense blue).

[Fiebre Verde]

Not a common specimen in that area.
Any patches of host rock on the opposite side?
Gérard

[Bergur_E_Sigurdarson]

Yes, the Dolomites sit on a light grey matrix :-)

[Fiebre Verde]

[Bergur_E_Sigurdarson]

Nope, the actual matrix parts are quite solid.
Attached a half-decent phone-cam picture to show the back.

[Fiebre Verde]

[Bergur_E_Sigurdarson]

A cute quartz cluster from Santander, Colombia.
I'm not 100% on whether it's from La Belleza or up the valley La Playa (I'm guessing they're the same "municipio").
My sources tell me there are little workings all along the river there and hard to tell from which they come each time (the usual secrecy in Colombia doesn't help).

I got this with a couple more pieces, all purportedly from the same place, but they are just distinct enough that I would think they would come from that area, but just not the same little working.

[Tobi]

Outstanding quartz specimen!

[Bergur_E_Sigurdarson]

Quite large crystal of Euclase, with several smaller ones in matrix.

Although the piece seems to have suffered a bit in the ground or extraction, the main crystal has only that missing piece on top right.
The bottom half of the crystal is very crumbly and a couple of cleavege lines run up it.
Still a very good piece as I've not seen many of this size.

Not perfectly sure about the composition of the matrix, but seems to mostly be some deteriorated carbonates (calcite and/or dolomite?) and on the back there is an eroded pyrite crystal.