FMF - Friends of Minerals Forum, discussion and message board

[Jan Erik]

Here we have a rather huge crystal of Phosgenite from Touissit, Oujda, Morocco. To me it looks like a floater, with all the sides intact, and the two main sides like kind of stopping the crystalisation during the prosess. Or maybe the pocket, crack or whatever the conditions have been, must have colapsed in some sort. Could anybody of you out there tell me how this big crystal have been developed?

The crystal is 14 x 7,5 x 4,5 cm in size

[Carles Curto]

Usually, in Touissit, most of the secondary carbonates an sulfates directly relate to lead (specially Anglesite, Cerussite and Phosgenite) are directly in contact with Galena, that use to be very altered, even being a black powder that, with the time, completely disappears and leaves this kind of rough surfaces.

[Jan Erik]

Thanks for your answer Carles. But if that, why do not the hole crystal got that surface? Is it maybe like this: In this case the galena has not filled all of the space where the phosgenite was developed? Curious about a new answer Carles.

[Carles Curto]

In your case, probably, phosgenite was between two pans of altered galena. Galena was primary and Phosgenite is a secondary product, growing in fissures and vugs in massive or grained Galena. Then, the faces that are not in direct contact to Galena are free and growth clean and bright.