Fluorescent mica from three different localities
Last year, one of my partners and I found lots of SW UV reactive phlogopite in the Lower Laurentians, Quebec, Canada, often associated with SW blueish-white diopside. I found it pretty nice under shortwave, but had no other fluorescent mica group minerals to compare it with, except some polylithionite specimens from Mont Saint-Hilaire. Since this phlogopite is brighter than all my MSH polylithionites, I knew our find was interesting, since MSH polylithionites are popular among fluorescent mica collectors; but I had no specimens of the also popular polylithionite from Greenland to make a better brightness comparison.
I recently acquired a small, modest but very bright Greenland polylithionite, so I could finally get a better idea of how good our find actually was.
As shown in the picture below, our phlogopite is nearly twice as bright as MSH polylithionite, so it's at least a decent fluorescent mica species; however, it's still far behind Greenland polylithionite. I will now need to acquire a specimen of phlogopite from Afghanistan to complete my test!
Shown below is the shortwave response of the three specimens; the larger one on top is the phlogopite from the lower Laurentians; on the lower left is a polylithionite rosette from MSH, and the bottom right specimen is Greenland polylithionite.
Phlogopite from the Laurentians: 11,9 cm X 7,4 cm X 3,1 cm
MSH polylithionite: 4 cm X 3,9 cm X 1,5 cm
Greenland polylithionite: 5,2 cm X 3,3 cm X 1,1 cm