FMF - Friends of Minerals Forum, discussion and message board

[Robson Vieira]

Hi everyone. I found some amygdaloidal basalt samples in a basalt quarry and one of the pieces has an acicular mineral among some Analcime. It was not possible to perform tests in order to identify such mineral, because it is small, brittle, and is in a difficult location on the stone, into the Analcime geode.
If you can help me with the identification, I would thank you a lot.
Regards from Brazil

[Tom Tucker]

Looks like mesolite, or related needles. Can you give the quarry location ? Thank you, Tom

[Nick_G]

It looks like natrolite to me, which is found as acicular crystals in amygdaloidal cavities on basalt. The cavities are formed from expanding gas bubbles in the cooling rock, which then get filled with other minerals such as calcites and zeolites.

[Justin Hickok]

As usual I'm probably wrong but I guessed millerite. 😬

[John Betts]

Of the acicular white minerals associated with analcime, natrolite is more likely than mesolite or scolecite. Definitely NOT millerite.

[Bob Harman]

Agree with JOHN B, definitely NOT millerite.
Why? Because not only is the geologic setting wrong for millerite, but blowing the photo up shows the acicular needles to not be silvery/brassy metallic as they should be with millerite (NiS).

And JUSTIN, I really suggest you sit back, not post, but just read what is being said and learn from others with more experience and knowledge. BOB

[Justin Hickok]

Actually I think many folks here have become complacent and rather pompous. And I think maybe some of you would be better off in a private forum.
It seems to me you would rather talk amongst your professional selves than actually teach.
And that's fine. Its your forum!

[Robson Vieira]

Thanks for all. I had thought it could be both natrolite and/or scolecite, but is difficult to decide. The exact location is the very little and unkown town of Terra Roxa, São Paulo, Brazil. It is in the north of the state, in a geological district called "Cuesta Basaltica", where basalt and related predominate.

[Robson Vieira]

20°45'04.8"S 48°24'00.5"W, exact location coordenates.

[John S. White]

Justin. I want to apologize for Bob's rudeness. That is not typical of the responses that you should get from members of this Forum and I am very sorry that this occurred. Please don't give up on this forum.

John

[Jordi Fabre]

[Matt_Zukowski]

I think John was right to call Bob Harman out on this. Bob simply should not have called Justin out like this without PMing Justin and the admins of this forum. But Bob H is also a good member of this community and should be supported. I think the solution is a mutual understanding. Bob H should be more constructive in his methods to improve this forum we value. But at the same time Bob H should ABSOLUTELY not take this as a slight because I know I speak for all of us when I say that Bob has shared with us loads about Midwest minerals specifically, and other good things, and I want him to be a part of FMF. I value Bob Harman’s contributions to FMF.

Justin, I think I know where you are buddy. When I found a forum of like-minded mineral geeks, I totally wanted to jump right in. Over time I learned that I learned more when I let the threads build up on their own. I think I have found ways to contribute, and I think your enthusiasm, should you choose to express it here with us, will lead you places to contribute too. Lurk around for a while. I think you will find it is worth it.