FMF - Friends of Minerals Forum, discussion and message board

[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.

[Fiebre Verde]

[Bergur_E_Sigurdarson]

Small but perfect little Emerald sitting on "wings" of Calcite... I called it the butterfly... but maybe it's so small, that just fly would be more appropriate :-)

[Bergur_E_Sigurdarson]

Before the lockdown I had to leave Colombia for a few days and went for a quick weekend hop to Lima, Peru. I used the opportunity to get some specimens from there.

Didn't have much time to prepare, find out where it would be best to buy and was feeling a bit underwhelmed by the offerings I saw (possibly because I wasn't in the "right" places and had little time). But upon my return and going through Peruvian material on the internet I'm a lot more pleased with what I got.

Here are some of the pieces, just in the order that I've been taking pictures.

As those were all purchased in Lima, I can only rely on their locality being what I was told (though I have scoured Mindat to verify that similar material is coming from those localities).

[Bergur_E_Sigurdarson]

The biggest microcline feldspar I've ever found myself, and I believe it's a manebach-twin, tho parts of it are missing.
I wasn't fortunate enough to find the pocket came from (I was just going through loose material, probably tailings from the old prospect), but expect it had some very nice things in it.

I was allowed onto the property next to the Little three mine near San Diego where I stumbled across this piece and a couple of small quartzes and even parts of the orange spessartine garnets the area is known for.
Judging by mindat, the property is located where the "Cable mine" used to be.
https://www.mindat.org/loc-91172.html

The owners showed me a huge ~25cm tall piece of quartz they'd found when digging some foundations, my little quartzes are just a couple of cm.

[Bergur_E_Sigurdarson]

I got this and a few more specimens at Peñas Blancas in the beginning of the year.
This one has a faden like line running through the quartz and in the same direction a line runs through the fluorite. (Also "faden" fluorite growth?)

I really like this piece as well as the others as they have less common combinations from there as well as in this case, a very unusual shape, especially for the fluorite.

When I got it it had some quite damaged aragonite coating it in parts, so I did etch it away with acid. The fluorite was already with a satin finish before that treatment, and the areas that had the aragonite and those that were exposed seem equal and same as before the acid (only needed about 15minutes to either dissolve or dislodge the coating)

I also have a piece that has the minerals more intact and won't be using acid to remove the aragonite and calcite there, but the photos I have at the moment don't do it justice and sadly even this one is just taken on my phone.