Discussions

╳Discussions

Groups

Recent Images in Discussions

Field Collectingetched sphalerite from dalnegorsk; how did they form?

24th Apr 2024 19:14 UTCJean-Francois Carpentier Expert

Sphalerite

2nd Sovetskii Mine, Partizanskoe Pb-Zn deposit, Dalnegorsk, Dalnegorsk Urban District, Primorsky Krai, Russia

Hello, I've obtained a Sphalerite specimen (overall 11 x 5 x 4 cm) that features a strange, deformed and melted appearance (see attached video).

they are actually several holes, up to 1 cm wide, that run completely through the specimen; minor Quartz points are associated.

A very similar specimen has been posted on Mindat by Norman King (see above). does anyone know how such specimens formed? natural (caustic) dissolution?

thanks

25th Apr 2024 09:03 UTCRalph S Bottrill 🌟 Manager

The holes could be formed by acid solution of more soluble minerals, maybe stalactitic calcite?

26th Apr 2024 13:54 UTCPavel Kartashov Manager

These are holes after dissolution of carbonate grains. And I don't sure that natural dissolution.

Carefully examine your sample under binocular for the presence of small grains of carbonates. I assume, you won't find them. In case if you'll find them, we will have to admit that this dissolution was natural.

26th Apr 2024 14:47 UTCKevin Conroy Manager

Galena from Dalnegorsk can also exhibit what may be dissolution features. I haven't tried to find out how this happened, I just enjoy the oddity of these specimens.

26th Apr 2024 15:54 UTCPhil Richardson

I also have a dissolution sphalerite from Dalnegorsk, similar to yours, and I'll post later today. And yes to Kevin, the galena from there can exhibit very unusual growth and/or dissolution.

26th Apr 2024 20:16 UTCPavel Kartashov Manager

Obviously, I didn't make myself clear. These structures are not associated with the dissolution of sphalerite itself, but with the dissolution of a mineral that grew simultaneously with sphalerite. The structures on the surface of sphalerite are induction hatches of joint growth.

In other words, structure inside cavities aren't structure of dissolution, but ones of previous growth.