Take a step back in time with the Ball Aqua Vintage Regular Mouth Quart 32-oz. Glass Mason Jars - Set of 4 Near the turn of the century, the color was unexpectedly created when the minerals in the sand used to make the glass jars mixed to form a gorgeous blue color. These beautiful aqua jars became popular for preserving and storing jams, jellies, and other recipes. You can replicate that experience with these collector's edition mason jars with the added assurance of Sure-Tight lids, which will keep your preserves fresh for up to 18 months. Jars and lids are BPA Free. Great for crafting, too. From a non-smoking and pet-free environment. Fast shipping always!