Yep, according to the modernists, your birthstone is supposed to be either the blue topaz or the turquoise, and according to the traditionalists, it could be zircon, turquoise, or lapis lazuli.
http://www.gems4friends.com/~lorraine/birthstones.html
I need PriaposLovs to come up with a good one for this, as I haven't been able to.
-- Nanaea