CiM Blue Arrow Frog - named for that colourful poison frog - Dendrobates tinctorius azureus - the whole poison frog thing is very interesting - you should read it. They get their poison from their diet - not by manufacturing it, for instance.
And maybe make a frog bead too. Turquoise frit. Some black frit for the dots - or maybe a dark iris reduction frit?
Anyway, this super pretty opaque dark blue is
virtually indistinguishable from Effetre 242 Medium Lapis. How
indistinguishable, you ask?
Well - that centre bead has dots of Medium Lapis on it.
Maybe from this angle?
Yep - that's how close they are. I think you can fairly safely consider Blue Arrow Frog and Medium Lapis to be interchangeable.
What a wonderful colour. Mmmm - bluuuuuuue.