Post by nemesis21 on Nov 1, 2017 11:29:11 GMT -5
I got a cheap UV bulb[long wave] and am slowly going through some of my rocks to see what glows. A lot of the prairie du chien chert/chalcedony/agate stuff has some orange and yellow fluorescence. The fluorescence only appears to be in the areas that are translucent(agate/chalcedony) under normal light. All of this material is from the Twin Cities area of Minnesota except the coral which is from near Winona, MN.
I found a site [link] that basically says that this can happen, but really doesn't say what mineral(s) are the cause of it. I'm sure this is due to some mineral impurity or leftover organic matter. If anyone has any insight/experience in this area I'd love to hear about it.
I put a few pictures up to show what it looks like under UV, but my camera really doesn't photograph it very well. The orange/yellow colors are a lot brighter than the pictures show and the blue is picked up too much.
Also, If anyone can recommend a cheap hand held UV bulb/device I'd appreciate it. I'm thinking about maybe occasionally searching for rocks at night under UV now. Too bad lakers don't glow under UV like this!
I found a site [link] that basically says that this can happen, but really doesn't say what mineral(s) are the cause of it. I'm sure this is due to some mineral impurity or leftover organic matter. If anyone has any insight/experience in this area I'd love to hear about it.
Quartz in its massive form (not chalcedony) usually does not fluoresce. However some of the quartz crystal druses and cherty bands from the Ordovician Prairie du Chien Group will fluoresce faintly yellow, orange or green. Such fluorescing quartz has turned up in quarries and road cuts near Hudson, Spring Valley, Nelson and Green Lake, so there are doubtlessly other occurrences. [link]
I put a few pictures up to show what it looks like under UV, but my camera really doesn't photograph it very well. The orange/yellow colors are a lot brighter than the pictures show and the blue is picked up too much.
Also, If anyone can recommend a cheap hand held UV bulb/device I'd appreciate it. I'm thinking about maybe occasionally searching for rocks at night under UV now. Too bad lakers don't glow under UV like this!
