The rarest blue sea glass color. Sometimes called "electric blue", this vibrant color reminds us of the color of the deep blue ocean. It was rarely used in bottle manufacturing and if it did originate from bottle glass was likely from an antique seltzer bottle.
On the Pacific coastline, where there is a vast amount of mariner traffic through inlets and islands there is a need for signal lighting. This greeny blue color was very often used for signal lantern glass, channel markers etc. The larger the lantern or light, the thicker and heavier the glass was. This photo at left shows a rare, intact buoy lantern found years ago washed up on a Pacific, west coast beach.