Fossil replaced by calcite?

[himmelangst]

My preschooler found this on a hike in western pa. We scoured our Audobon and cannot figure out what it is a fossil of, if it is one at all. I am afraid to ruin it by cleaning it. UV reactive, fluoresces bright yellow-green. Thanks to all you brilliant folks for your help!

[Arizona Chris]

Stalagmite from cave?

[patelinho7]

That looks like a piece of quartz to me. But PA has lots of fossils, so keep looking!

[debivort]

The fluorescence strongly implies calcite over quartz, as does the lustre and lack of conchoidal fractures to me.  I think it might be a calcite fossil, but could also be geologic. Hard to tell without more detailed preservation.

[patelinho7]

I'm having trouble seeing the fluorescence. I only see the effect of light through a translucent rock, as well as UV light reflecting off it. Wouldn't the color be significantly different from the color of the rock if it was fluorescence?

[debivort]

There's always a question of how a digital camera picks up the wavelengths, but what I see is that the light straight from the UV source (to the sides of the specimen) is purple, and saturates the blue channel, exactly as you'd expect from a broad spectrum near UV source like an LED. But the specimen itself is yellowish-white, meaning the camera RGB sensor is picking up red, green (longer wavelengths) and some blue. Pretty much exactly what I'd expect. @himmelangst should confirm what they see by eye.

[himmelangst]

20 hours ago, debivort said:

There's always a question of how a digital camera picks up the wavelengths, but what I see is that the light straight from the UV source (to the sides of the specimen) is purple, and saturates the blue channel, exactly as you'd expect from a broad spectrum near UV source like an LED. But the specimen itself is yellowish-white, meaning the camera RGB sensor is picking up red, green (longer wavelengths) and some blue. Pretty much exactly what I'd expect. @himmelangst should confirm what they see by eye.

Yes that is exactly what happened, it was the best photo i could get to the naked eye. It really looks vivid neon yellow/green in real life. The mineral is orange and the green color on the exterior is actually organic material. What is the best way i can remove the scuzz without damaging the specimen? I am afraid to damage it because there are fibrous needlelike crystals along the edge that are very fragile. Thank you for your help.