The amount of the aqua color will vary by bead, but basically there is a body of the aqua which is covered in a clear Murano Glass. For an idea, look at these earrings which are in our V Marino.
https://www.venetianbeadshop.com/Eternity-Ring-with-Tosca-Gold-Foil-Murano-Glass-Bead-Dangle-Earrings-with-Gold-Fill-Findings_p_23917.html