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  • Writer's pictureHelaina Ferraioli

Cobalt Blue Glass: Through the Ages

Updated: Jun 3, 2022

While Cobalt blue glass has been discovered in archeological sites around the globe, it wasn't until the late 19th-century that the colored glass started to be used commercially. Yet, no matter how old a given piece, the stunning bright blue color of its ore remains appreciated by both antique collectors (for its value) and contemporary families (for its aesthetic) alike. But don’t be too quick to associate the color with Depression-era glassware alone - this pigment actually has a deep and rich history throughout the ancient and modern world.

Ancient origins of cobalt ores

Ores containing cobalt have been used since antiquity as pigments to impart a blue color to porcelain and glass. The earliest known example of cobalt aluminate glass dates to a lump found from about 2000 BC in ancient Mesopotamia, very possibly intended for use as a pigment. About five centuries later, Cobalt oxide smalt appeared as a pigment in Egyptian pottery, and soon after in the Aegean region. This is the pigment normally known as smalt.

Photo 1 (Left): Abbasid Cobalt-Blue, Green, and Grey Tin-Glazed Pottery (9th Century Mesopotamia. Photo 2 (Right): Cobalt-blue glass beads found in 3,400-year-old graves in Denmark, came from ancient Egypt.

The pigment was not limited to the Mediterranean regions of ancient society: Chinese porcelain used smalt glazes from the Tang dynasty onwards. Going back even earlier, some Chinese cobalt glass was found from the Zhou dynasty (1122–221 BC)! Cobalt was used as a pigment throughout Central Asia from the 13th century forward.

Much later, European artisans and glassmakers began to utilize the pigment. A large quantity of smalt was purchased for the decoration of the gallery of Francis I of France at Fontainebleau in 1536, and is commonly found in European paintings from the 15th to 17th centuries. Most notably, it is found in Hans Holbein the Younger's portrait of Sir William Butts (ca. 1540), in Michael Pacher's painting "The Early Fathers' Altar" (ca. 1483), and in the frescos of Domenico Ghirlandaio (1449–1494).

Cobalt Blue glass' modern incarnation stems from the process used for producing cobalt smalt glass at the Blaafarveværket industrial manufacturing center in Norway in the 19th century. It involves a process of smelting cobalt oxide together with quartz and potassium carbonate. The smelt is incorporated into molten glass mixtures, and the result is an intensely blue glass-like substance that was ground and sold to producers of glassware and porcelain.

Cobalt blue’s modern revival

At the turn of the 20th century, hand-crafted glassware had become a household staple for wealthy families. Delicate crystal cups and plates were manufactured in small shops called hand houses, where intricate hand finishes were added to glassware. As the cost to make such detailed, handcrafted glassware was high, it was considered a luxury item and was nearly inaccessible to the lower and middle classes.

But in the 1920s, certain glassmakers realized that the need for affordable, attractive glassware existed for working class American families. As this market was nearly untapped, glassmakers pounced on the opportunity to expand their business, and the production of unfinished glassware (at accessible price points) was born!

Just as quickly as this new market was tapped, the tides of history turned towards affordable glassware for the majority of American families. When the Great Depression hit, expensive glassware fell out of favor among consumers, and what we know today as “Depression glass” skyrocketed in popularity among female consumers who desired the aesthetics of expensive glassware at a fraction of the cost it had once been. Between the 1920s and the 1950s, over twenty manufacturers produced Depression glass, including Jeanette, Hazel Atlas, and Anchor-Hocking.

The Great Depression’s iconic glassware

In order to meet the necessary price-point of struggling consumers, manufacturers had to optimize their production processes so that they could sell a twelve-piece dinnerware set for under two bucks (note, the Average family was only bringing in a measly $17 per week). Thanks to the industrialization of glass objects, the manufacturing process was kept relatively inexpensive.

Despite this seeming “good nature” of glass manufacturers who promoted affordability, the same old advertising tricks and ploys were still being used to sucker the American working class into adopting the glassware, even if they didn’t really need it. Companies began offering Depression glass objects as promotional items: from glass pieces being included in cereal boxes, to giving them away at movie theaters and gas stations to retain loyal customers. Consumers, always on the lookout to save money, took advantage of these promotions and slowly built complete dinnerware sets by collecting the promotional glass goods over time.

Characteristics and collectability

In the years following Depression glass production, many reproduction pieces entered the market, making the authentic era glassware more valuable and more important to spot. At its peak, each Depression glass manufacturer developed favorite colors, shapes and patterns that can today be identified as originals. Authentic Depression glass, while produced with the same speed as reproductions, holds more historical importance, and for some, an unexplainable level of charm that reproductions simply don’t match.

On the topic of speed, Depression glass was produced so rapidly and at such a medium quality that the pieces remained affordable throughout their production. On the other hand, the perks of speed and “medium” quality lent way to a notable amount of flaws such as bubbles, molding imperfections, and inconsistent coloring. However, these “flaws” rarely affect the value of the wares, and many collectors actually seek out and cherish the inconsistencies that, again, hold a historical significance inside of them.

While opulent and fashionable glassware was definitely not the top priority for the overwhelming majority of struggling American families, a select few were still in search of high-end glassware. For this relatively select segment of the market, higher-quality, handmade glassware called “Elegant glass” was produced; these pieces were often clear, contained no imperfections, and featured designs ingrained in the glass (rather than

raised patterns featured in Depression glass).

But overwhelmingly, the largest selection of Depression-era glassware is in the mass-produced, medium-quality Depression glass that was made to please the majority of Americans who were looking to live dignified and colorful lives, despite their economic circumstances.


Yesterday's News is always bringing in Depression-Era glass, as it was used by so many families throughout the 1900s. Right now, we have a huge assortment of Cobalt Blue Depression glass left in stock - including plates, cups, and serving dishes. Check out our latest Instagram post to see what we have in stock!




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