Log InRegister
Quick Links : The Mindat ManualThe Rock H. Currier Digital LibraryMindat Newsletter [Free Download]
Home PageAbout MindatThe Mindat ManualHistory of MindatCopyright StatusWho We AreContact UsAdvertise on Mindat
Donate to MindatCorporate SponsorshipSponsor a PageSponsored PagesMindat AdvertisersAdvertise on Mindat
Learning CenterWhat is a mineral?The most common minerals on earthInformation for EducatorsMindat ArticlesThe ElementsThe Rock H. Currier Digital LibraryGeologic Time
Minerals by PropertiesMinerals by ChemistryAdvanced Locality SearchRandom MineralRandom LocalitySearch by minIDLocalities Near MeSearch ArticlesSearch GlossaryMore Search Options
Search For:
Mineral Name:
Locality Name:
Keyword(s):
 
The Mindat ManualAdd a New PhotoRate PhotosLocality Edit ReportCoordinate Completion ReportAdd Glossary Item
Mining CompaniesStatisticsUsersMineral MuseumsClubs & OrganizationsMineral Shows & EventsThe Mindat DirectoryDevice SettingsThe Mineral Quiz
Photo SearchPhoto GalleriesSearch by ColorNew Photos TodayNew Photos YesterdayMembers' Photo GalleriesPast Photo of the Day GalleryPhotography

Identity HelpCu-Austinite vs Conichalcite from Ojuela

27th Apr 2012 18:02 UTCPeter Hargis

Looking through the various photos uploaded for the Ojuela Mine, I'm noticing that gemmy Cu-Austinite and gemmy Conichalcite look very similar (and even the Arsenodescloizite and Cu-Adamite can look similar). One of the differences I notice is that the gemmy Conichalcite comes in small distinct xtals more often than the Cu-Austinite (more of a mass of xtals). Does anyone know of a good "eyeball" test to tell the difference between the two?


For instance, these two look similar to me...

http://www.mindat.org/photo-233419.html

http://www.mindat.org/photo-31557.html

27th Apr 2012 18:45 UTCRichard Gunter Expert

Hi Peter:


I did a B.Sc. thesis in 1977 on the Ojuela Mine Conichalcite-Austinite Series and found that there is no visual method of determining the difference between phases. I also found that it is a three component system with significant Pb in some of the crystals. The Pb altered the unit cell dimesions sufficiently that even XRD was not always accurate. The sample posted on my page has XRD cell size and microprobe data so I know what that sample is. The thesis was completed before the characterization of Arsendescloizite but I did not find any samples that were rich enough in Pb to qualify as a new phase.

27th Apr 2012 19:04 UTCPeter Hargis

Interesting... So I wonder if it would be more accurate to list a mineral as being from the series instead of a particular member of the series?


Have you thought about adding your research to the mineral page for the series, as a reference?

27th Apr 2012 19:24 UTCRichard Gunter Expert

Hi Peter:


Unless the samples are colourless, in which case they are probably Austinite, all of the Conichalcite-Austinite samples are members of the series. I never thought of putting the cell's size and microprobe analyses with the posted sample but I will do that to assist others.

27th Apr 2012 19:44 UTCRichard Gunter Expert

Hi Peter:


I have added the cell size and microprobe results to the note on photo #428254. I hope this helps clear up the confusion a little bit.

27th Apr 2012 20:17 UTCPeter Hargis

I appreciate the help!
 
Mineral and/or Locality  
Mindat Discussions Facebook Logo Instagram Logo Discord Logo
Mindat.org is an outreach project of the Hudson Institute of Mineralogy, a 501(c)(3) not-for-profit organization.
Copyright © mindat.org and the Hudson Institute of Mineralogy 1993-2024, except where stated. Most political location boundaries are © OpenStreetMap contributors. Mindat.org relies on the contributions of thousands of members and supporters. Founded in 2000 by Jolyon Ralph.
Privacy Policy - Terms & Conditions - Contact Us / DMCA issues - Report a bug/vulnerability Current server date and time: April 20, 2024 00:58:16
Go to top of page