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EducationChrysocolla in Chalcedony Enhancement

27th Mar 2018 10:42 UTCmario tapilouw

Hi All,

I am wondering if there is anyone knows about enhancement of Chrysocolla in Chalcedony. I was told that this stone can change its color, from brown into beautiful green or blue color, so I would like to ask if there's anyone got any experience with this mineral?

Thank you very much.

27th Mar 2018 16:16 UTCScott Rider

Chrysocolla is normally blue, blue-green naturally, and I guess it could be brown (Mindat has that as a color, but I doubt they are popular and probably why I have never seen one)... But I doubt chalcedony would change the color, maybe be a barrier to oxidization though... Did you mean enhance the color perhaps?

28th Mar 2018 02:17 UTCDoug Daniels

In my 40+ years as a collector (and geologist), I'v e never heard of brown as a color for chrysocolla. Then again, chrysocolla isn't really a mineral....it doesn't have a definite composition, nor a definite structure (a minerloid), so, who knows? If it does occur in a brown color, I don't know how it would change to the commonly known blue-green. And as Scott mentioned, if it is in chalcedony, any chemical changes would be highly problematic.

28th Mar 2018 02:19 UTCmario tapilouw

Yes, some kind of oxidation. It seems to me that the brown color is a kind of dirt trapped inside the crystal and somehow it dissolve (oxidized perhaps) and find its way out of the crystal making the crystal clearer. This makes the crystal seems to have a color change.

28th Mar 2018 02:55 UTCWayne Corwin

mario

chrysocolla is not a crystal, read what Doug said.

28th Mar 2018 02:56 UTCWayne Corwin

it might be brown with iron stain, and iron out might turn it green again.

28th Mar 2018 11:39 UTCReiner Mielke Expert

" I was told that this stone can change its color, from brown into beautiful green or blue color" Maybe this sentence is a translation issue but it cannot change it's color by itself. Humans can change it's color with colored dyes or other chemical means but other than that the color cannot be changed.

29th Mar 2018 07:12 UTCmario tapilouw

Hi All, thanks for the replies. I think it's stain, either iron or copper.

29th Mar 2018 22:16 UTCDave Owen

I think you may have it backwards. The chalcedony does not change the color of the chrysocolla but rather the chrysocolla changes the color of the chalcedony. As for brown, no idea.

29th Mar 2018 23:06 UTCDave Owen

To ad to my previous thought possibly someone has gotten the idea that the brown iron minerals often found in chalcedony which sometime produce fire agate are somehow transformed into the bright blue. Maybe this is because they are both found in Arizona.

30th Mar 2018 13:34 UTCRolf Luetcke Expert

I wanted to add a few things here. Doug said he had never seen brown chrysocolla and I have tried to figure a few things out about chrysocolla since it is on the edge of being a mineral. I have often seen black material that is near or sometimes grading to the blue chrysocolla. It was at times called "tenorite" and when actually analyzed by a couple of people, it analyzed as chrysocolla, even though it was black. I have seen this often in Arizona copper mines where tenorite is listed as a mineral at a mine and from my own experience it is chrysocolla that has turned black from some kind of alteration. Don't know if iron or manganese is the culprit but so much of the chrysocolla I have seen alters from the nice blue to nearly black and I believe it is all under the chrysocolla umbrella name. At other posts where I had mentioned this it was said that chrysocolla really needs a reworking but nobody really wants to tackle this issue.

So, brown is a color I have seen in the above mentioned alteration process of the copper ores. Until the chrysocolla is studied fully, it will remain a big question. I do believe that the mineral tenorite I have seen at a number of mines in Arizona is not actually there but is the "black" chrysocolla instead.

31st Mar 2018 02:04 UTCDoug Daniels

Rolf-

Sounds like a thesis, if someone could scrounge up the funding for such an esoteric subject (that is, just not relevant to the price of tea in China these days).

31st Mar 2018 03:21 UTCAlfredo Petrov Manager

Discussions about chrysocolla usually reach a dead end because there are so many different substances that use that name: x-ray amorphous Cu-silicate gel; some poorly crystallized Cu-silicate; silica gel ("opal") colored blue by microinclusions of some crystallized Cu mineral; crystallized silica (chalcedony) colored blue by Cu minerals; mixtures of the above or things so impure they don't show the classic blue color... Lapidarists don't necessarily use terms the same way mineralogists do. Many mineralogists aren't much help because the majority of mineralogists aren't very interested in poorly crystallized substances and aren't willing to spend a lot of time on them. So I think the only thing we can all agree on is that the topic is a mess, and likely to stay that way for a while. ;))

2nd Apr 2018 17:32 UTCRob Woodside 🌟 Manager

Chrysocolla is so ill defined, one should expect a rainbow of colours. Here's a yellow one. Chrysocolla is possibly just coloured silica gel. https://www.mindat.org/photo-737016.html

To disabuse those of you who think Chrysocolla is blue or greenish blue check out the new header photo and colour box https://www.mindat.org/min-1040.html

13th Apr 2018 08:41 UTCmario tapilouw

Wow, thanks for the explanation..

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