FMF - Friends of Minerals Forum, discussion and message board

[MrOHBrown]

Hello folks,

I am a new member and have recently found an unexpected passion for rocks.

This passion is well facilitated by the fact that I am a Chemistry teacher and I have access to an extensive, but neglected, rock collection that I am excited about bringing order to.

One drawer is labelled "Cerrusite and Galena" - However what is in the drawer is what appears to be a LOT of Quartz with beautiful veins of Galena and Pyrite.

Adding HCl to the white crystals yields no reaction leading me to believe it is Quartz, and no picture of Cerrusite, nor the Cerrusite that I have at home, looks anything like the specimens I have been studying.

I am willing to bank on it being Quartz but would appreciate your input.

[Jordi Fabre]

Some chance to publish a photo here? Anyway, you could try if it scratch the glass. If yes, then for sure is not Cerussite but possibly Quartz.

Jordi

[Pete Modreski]

Dear MrOH,
Likely you are right that it's just quartz that contains the galena etc., because quartz is certainly a lot more common than cerussite. Possibly, there is a small amount of cerussite present, perhaps coating some of the galena?
There should be many easy ways to distinguish cerussite from quartz. Pieces that are mostly cerussite would feel quite a bit heavier than a comparable size of pure quartz (unless it's full of galena too). And as Jordi says, hardness would be a very easy test; quartz would scratch glass, cerussite (H = 3 to 3.5) would not; or, you can easily scratch cerussite with a knife, quartz not.
Pete Modreski

[MrOHBrown]

Hello people,

Please, call me Owen.

I have attached just one specimen of the rocks I mentioned earlier. There is little difference between the specimens so I think this one will assist you.

I have no doubt that the specimens contain Galena and Pyrite.

The White material scratched glass, furthering my suspicions that it is Quartz.

You can notice some othe reds and oranges, I put this down to other Iron compounds.

Please assist!

[Les Presmyk]

Looks like quartz to me and a fairly typical ore specimen at that. If it were cerussite, the piece would be noticeably heavier. If this were cerussite, the sulfides would have oxidation halos around them rather than the very crisp surfaces.

[MrOHBrown]

Ha ha, I don't mind it being an average-joe specimen, I just want it to be accurately named!

Based on your input there is NO Cerrusute in the drawer in queston and the sticker as been removed.

Thanks for your help!

[Joan R.]

Hi,
I would like to say that if you have a UV lamp (very cheap, used to detect false bills), Cerussite usually shows fluorescence under UV light, and then you could check if in the fluorescent area there is something interesting.