Thanks Art -
Another tidbit of info is that there are a few chevrons in the Picard book that have layers described as white but look like light grey with white flecks, same as my bead but slightly lighter in shade.

I'm still not sure about the outermost layer since it is thin, and not backed up by the usual solid white. So it looks like translucent greenish in strong daylight, but in other light looks just like the inner layer which is more a match for the usual dark blue seen on 7Ls.

Here is a pic taken in sunlight, with 7L blues on each side. To my eye the outer layer is definitely greener than the blue on other chevrons. I have two opinions that this would be called "teal", which I think is the same as the "translucent blue-green" described in the Picard book as a color found in 7Ls.

The color rendition is difficult on this bead. Cameras do not have the same dynamic range as the human eye!