From our experience, aqua blue is a sea glass color that seems to be diminishing the fastest especially along Pacific and Caribbean shores. Some glassware that it can commonly originate from is canning jar and electric insulator glass.
Both are items that are almost never used or produced for use today, especially in this color. This is adding to the growing rarity of this "color-of-the-ocean" shade of sea glass and it's our best selling jewelry color.
Aqua blue bottle stopper flat top (at right). This well frosted, thick and rounded (though it has a "flat" at the bottom) wheel of beautiful sea glass originates from an old glass bottle stopper. The stem has long been shaved off from decades tumbling at sea and what's left is this nearly round top. It was used to cap the top of a vintage sauce or seltzer bottle. © www.WestCoastSeaGlass.com