Petrified Wood (Chalcedony) from Western North Dakota, USA
A member of our Fluorescent Mineral group on FB wanted some pics of some beautiful petrified wood he found way out in the wilderness in North Dakota. I offered my services and he decided to ship a "thumbnail" out to me (it barely fit in my photography studio!). Very pretty material, fluorescent under all wavelengths. The green fluorescence under SW is obviously the opalized wood likely activated by the uranyl ion. Not sure what the orange fluorescence is from. It appears to be from a darker opalized seam of wood (not the bark as I initially suspected). Likely organic activators, but really not sure. Minerals are likely a combination of chalcedony and opal/agate.