FMF - Friends of Minerals Forum, discussion and message board

[Roger Warin]

Hello,
I would like to show you a very rare mineral from my collection: dufrenoysite.
Its globular habit is even rarer. In addition, it has a twin on (001)
Dufrenoysite is a mineral species consisting of an arsenic and lead sulfosalt with the ideal formula Pb₂As₂S₅.

[Herwig]

Mon cher Roger,
I have a very hard time believing that your specimen is dufrénoysite.
The color and the luster do not match this mineral: https://www.mindat.org/min-1324.html

If this were a crystal of dufrénoysite, it would be much darker, and would have a more metallic look.
Judging from the photo and the location, my first impression of what your specimen could be, is sphalerite.

Here is a link to the mindat photos of sphalerite from Lengenbach:
https://www.mindat.org/photoscroll.php?frm_id=pscroll&cform_is_valid=1&searchbox=sphalerite+from+lengenbach
Hope this helps.

I'm looking forward to seeing you at the Mineral Show in Hannut this weekend!

Cheers, Herwig