FMF - Friends of Minerals Forum, discussion and message board

[bob kerr]

I got this wonderful Milpillas Azurite rose floater from Jesus Valenzuela - he did not know what is was and marked it way down due to the off coloring that you can see in the photo. The dulling stain is only on the one area of the specimen and starts abruptly at the interface of the azurite crystal faces.

It doesn't appear to be malachite chatoyance - but maybe it is. I hope to have it tested to see what it is but I thought one of the experts on FMF may know.

thanks,
bob

[carlo11]

I have a plate with rosettes from Bisbee some of them having what I believe are hematite/goethite films. Maybe this one is the same, but I have to say, that to me it just looks like the azurite is dull in those areas not due to any coatings, maybe just because of localized light dissolution on that area, I couldn't really tell you for certain.

[RayStraw]

The stain appears to be green.

If so, this may be a pseudomorph to azurite.

Most of these pseudos start at the center of the area of attachment to the matrix.

The replacing malachite is almost always botyroidal in form and grows within the azurite.

As the pseudo progresses the malachite eventually reaches the surface and the surface of the azurite is breached.

The U of Arizona has some analysis technique to identify minerals without damaging the surface.

I would recommend identifying the smudge because it may not be malachite.

Hope this helps.

Ray