FMF - Friends of Minerals Forum, discussion and message board

[marius_md]

Hi to all reading this...
i was few days on a hike and found this nice stone ( pictures attached) and after getting home I taught what about buying a UV flashlight to see it under UV light as I saw on youtube... I was surprised it is fluorescent...

i would appreciate some opinions what it can be since where I live in Romania I don't have a place to go an check a "professional"

Thank you

[Peter Megaw]

Hi Marius, nice hike!

First guess is that it is calcite, if you can scratch it easily with a knife or nail and it fizzes if you put a drop of vinegar on it, that's probably what it is.

Calcite is commonly luminescent as you've seen. There are a lot of things that can activate luminescence, so you need to try another test. Get into a very dark room or closet and light up the white band with your UV flashlight for 20-30 seconds. Then turn it off quickly...watching closely to see if the luminescence lingers...and if so for how many seconds.

Do all these tests, report back and we should be able to narrow things down for you

[marius_md]

Hi...
Thank you for your replay...
1. tried to scratch it and no chance so I put vinegar straight on it and nothing happened
2. used UV flash light as you suggested and after 1 minute of exposure it takes like 2 seconds to luminescence to fade very fast

I guess my camera from my phone is not the best thing... the " white band " that is luminescent under UV light it "sparkle" under sunlight.
I was curious just to find something about cause for me is just a "rock" that looks like "bacon" and is nice to put it on display .
now that I've got a UV flashlight I will start hunting for more "rocks" on my hikes

[Peter Megaw]

If it's that hard and reactive it is probably quartz. The banded textures indicate it may be a vein or other fracture filling. Is the blue green color showing under UV or sunlight?

[marius_md]

Thank you for your replay / time Mister Peter

So... the band in the middle is hard and it doesn't react on vinegar, under the sunlight is white with sparkles if you change the angle of view , under the UV light still stay white only on complete dark gives some fluorescent luminescence, if I keep UV light very close to the band after30/40 seconds of exposure the 2 seconds of fading luminescence is yellowish to greenish "spectrum"

I hope it make sense what I wrote since native language is not english .

Best regards