Learning Center What is a mineral?The most common minerals on earth Information for Educators Mindat Articles The Elements The Rock H. Currier Digital Library Geologic Time

Minerals by Properties Minerals by Chemistry Advanced Locality Search Random Mineral Random Locality Search by minID Localities Near Me Search Articles Search Glossary More Search Options

The Mindat Manual Add a New Photo Rate Photos Locality Edit Report Coordinate Completion Report Add Glossary Item

Mining Companies Statistics Users Mineral Museums Clubs & Organizations Mineral Shows & Events The Mindat Directory Device Settings The Mineral Quiz

Photo Search Photo Galleries Search by Color New Photos Today New Photos Yesterday Members' Photo Galleries Past Photo of the Day Gallery Photography

Discussions

💬 Home 🔎 Search 📅 Latest

╳Discussions

💬 Home 🔎 Search 📅 Latest

Groups

Recent Images in Discussions

Identity HelpFluorescent mica in granite pegmatite

6th Aug 2010 12:17 UTCJyrki Autio Expert

Hello All

In attached picture is silvery gray mica with garnets from quartz and feldspar quarry Kemiö, Finland. Parts of mica, not all, fluoresce strongly lemon yellow in SW UV. Fluorescence occurs in certain areas of samples, while superficially similar mica in other parts does not show it at all.

?

Thanks

Jyrki

6th Aug 2010 16:50 UTCVandall Thomas King Manager

The mica looks exactly like muscovite based on association with almandine and being from a granite pegmatite. Muscovite does not commonly fluoresce, do you have a photo of the fluorescence? Is the fluorescence due to a coating or inclusions?

6th Aug 2010 19:18 UTCFred E. Davis

Polylithionite fluoresces a lemon yellow with SW UV. For example, look here MSH fluorescence. But I know nothing of the locality, so that's only a blind suggestion.

6th Aug 2010 20:07 UTCPavel Kartashov Manager

Apparently your muscovite adsorbed uranyl ion on its surface. Usual thing in pegmatites. The most foliated portions are more fit for solution penetration and ions transport. They are fluorescent. More massive portions don't fluorescent.

6th Aug 2010 20:48 UTCJyrki Autio Expert

Thanks for answers. Here is quickly made picture of it.

Jyrki

6th Aug 2010 21:33 UTCFred E. Davis

If the photo colors are reasonably accurate, I think Pavel is correct.

6th Aug 2010 22:54 UTCIlkka Mikkola

Hello Jyrki.

About thirty years ago Rautaruukki-company analyzed these kind of thin flecks.They were some unidentified

U-niobates.

Ilkka

8th Aug 2010 13:14 UTCVandall Thomas King Manager

BTW As far as I know, polylithionite has not been verified from any granite pegmatite in the world.

8th Aug 2010 15:28 UTCFred E. Davis

I stand corrected. Thanks!

10th Aug 2010 15:22 UTCMark Willoughby Expert

Howdy Jyrki,

Are the photos aligned?

If so it's not only the mica that's fluorescing!

Which would strengthen Pavel's suggestion, as it would appear that uranyl rich solution has come into contact with is and there are residual traces anywhere the solution could get into, flaws and cracks etc. as well as in the top layers of the mica.

If the photos are not aligned, then disregard this suggestion.

Here are the two photos overlain so you can see, it certainly looks like they are aligned to me.

10th Aug 2010 16:45 UTCPavel Kartashov Manager

Van King Wrote:

-------------------------------------------------------

> BTW As far as I know, polylithionite has not been

> verified from any granite pegmatite in the world.

Dear Van,

polylithionite is a typical mineral of agpaitic alkaline granite pegmatites - Khaldzan Buragtag in Mongolia, Darai-Pioz in Tajikistan.

See for example http://www.mindat.org/photo-205445.html, http://www.mindat.org/photo-202407.html and http://www.mindat.org/photo-202406.html - in two cases quartz marix is well visible.

10th Aug 2010 18:55 UTCChristian Ottesen

I came to think of this piece of pegmatite:

It is quarts and muscovite with some albite (at least i thought so..)

I have seen red fluorescense in Albite and Cleavelandite from sweden, but it has a very bright yellow/green fluoresence, from som of the "albite"? (In Shortwave)

it is from Skuleboda, Sweden

13th Aug 2010 16:12 UTCJyrki Autio Expert

Sorry I came back so late. It really is random fluorescence (from clouds of tiny dots). What I first thought about mica florescence seems not to be the case as explained in above posts.

I take this as an learning experience x.th time. Think first and ask later :)

Ilkka- Thanks also about corundum reference.

Mark- Pictures were aligned only by sight, not any real effort in it. Here attached is best picture I can take of about the same spot -UV in daylight, height about 10 mm.

Thanks

Jyrki

13th Aug 2010 17:42 UTCLogan Babcock (2)

what you have is uranyl salts within the rock. if you know the locality then look it up and look for fluorescent uranium minerals. now, do you have a geiger counter? if so, check it!

kind glowing regards, Logan.

13th Aug 2010 17:46 UTCJohn Duck

Hello Jyrki,

Another possibility is hyaline opal (hyalite). It typically will fluoresce a bright green in shortwave UV caused by the uptake of a small amount of uranium. It is often virtually invisible on close examination in visible light yet will produce the vivid green on exposure to UV. I see a lot of this in Maine pegmatites ranging from random specks to good coverage. It will coat various minerals so the fluorescent areas will not necessarily correspond to specific minerals.

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: May 3, 2024 03:41:13

Go to top of page