This is a Mid Century Parker Ink bottle with a paper label reading, "E.W. Parker - Super Quink Washable Royal Blue Ink". The bottom of the inkwell is embossed, "Parker - Made in USA - 2 FL Oz" - ? - and a circled letter "M". The blue diamond shaped bottle was produced in the 1960s. The Parker Pen Company introduced the Quink line in 1931 as an improved fountain ink that would not clog pens. It was advertised as an all-purpose ink, both water and mold resistant. It was quick drying and non-corrosive. My father, an avid bottle collector, found this bottle more than 40 years ago. It's in great shape, free from breaks or cracks. The label has faded somewhat over time (see photo closeups). The cobalt color remains vivid. The vintage ink bottle measures about 3" wide, 2" deep, and 2.5" tall.