FMF - Friends of Minerals Forum, discussion and message board

[texasdigger]

I'm looking at this termination and wondering a few things. I think the term trigonic applies but maybe only a mystical term...
1: Is it a modified termination?
2: Is it an etched termination?
3. Why the triangles?

[Peter Lemkin]

I'm not an expert on this, but is sure looks etched to me. Nice etch figures, at that!

[lluis]

Hi, Texasdigger

Well, tourmaline is trigonal
https://www.mindat.org/min-4003.html

So, triangles could be just the result of etching or just a consequence of crystal growing under determinate circumstances... I think in your case more second thing.

Nothing mystic. Just chemistry and crystallography.

And as Peter says, a nice piece, at least to my eyes!

With best wishes

Lluís