The 1920s favored colored or opaque glass, particularly in amethyst or cobalt blue. Then style mostly shifted to ornate stoppers on plainer bottles in the 1930s.

The first uses of cobalt blue were found in Mesopotamian aluminate glass circa 2000 B.C., said Pantone’s Pressman, with later occurrences in Egyptian pottery.

SARATOGA SPRINGS — Since its founding in 1872, Saratoga Spring Water has been sold in blue bottles. The color, chosen at first because light blue glass was cheaper at the time than alternatives ...

You can't see the code marking very well, but it looks like the so-called "I Inside a Diamond" logo, indicating the bottle was made by the Illinois Glass Co. in Alton, Ill., between 1915 and 1929.