FAQ

Frequently Asked Questions

What is uranium glass?

Uranium glass is a type of glass that contains a small amount of uranium oxide, typically added during the glass making process to create distinctive yellow-green to green hues. When exposed to ultraviolet (UV) light, uranium glass fluoresces a bright green glow which is one of its most recognizable characteristics. Different types (wavelengths) of UV-light cause stronger reactions in the uranium glass causing a more significant glow.

The amount of uranium used is generally very small, usually well below 2%, and primarily serves a decorative and coloring purpose rather than any functional one.

Is uranium glass safe?

Yes. Uranium glass is generally considered safe for display and handling even though the glass contains trace radioactivity. It contains very low levels of uranium and does not pose a health risk under normal use. We recommend treating it as decorative antique glass rather than functional tableware. Notable recommendations on handling include limiting surface scratching with cutlery in regards to plates and bowls and not using uranium glass in combination with highly acidic liquids. (Fruit presses, drinking glasses)

Why was uranium added to glass?

Uranium was added to glass because of its unique coloring properties and availability. Glass makers discovered that uranium oxide could produce vibrant yellow, green, and chartreuse tones consistently when mixed into molten glass. Uranium oxide also enhanced brilliance and clarity in certain glass formulas.

Long before concerns about radioactivity, uranium was valued simply as a pigment, much like cobalt (blue) or manganese (purple).

What other examples are there in regards to colored glass?

Colored glass has been produced for thousands of years. Ancient civilizations used minerals and metal oxides to color glass, including copper (green and blue), cobalt (deep blue), iron (green and brown), manganese (purple) and many more. The color largely depends on the element used, its oxidation state, the furnace atmosphere and the glass composition. Uranium joined this tradition relatively late, becoming popular in the 19th century as industrial glass making expanded and new coloring agents became widely available.

When was uranium glass first made?

The earliest known use of uranium in glass dates back to ancient Rome, where traces of uranium were found in yellow glass fragments from the 1st century AD. However, intentional and widespread production of uranium glass began much later, in the early 19th century, particularly in Central Europe. One of the earliest documented producers was in Bohemia (modern-day Czech Republic), where uranium-rich minerals were readily available.

Where was uranium glass produced?

Uranium glass was produced across many regions, each with its own styles and traditions.
In Europe the largest producing countries include:

Bohemia / Czechoslovakia which were among the earliest and most influential producers producing distinct glassware and pottery. Germany, which is known for precision-cut glass and decorative tableware. The United Kingdom specializing in matte Opaline based glass and more widespread coloring agents. France, known for it's ornate flower patterns on elegant Art Nouveau and Art Deco designs. Belgium known for it's opaque tan patterns on glass lighting fixtures and pristine colored drinking glass ware. The Netherlands known for it's distinct designs in various flower patterns and cut glass and Finland known for their post WWII production lines for beautiful ornate jugs and bottles.

Outside of Europe, production of uranium glass mostly took place in the United States producing on a large-scale from the late 19th century through the 1930s often being associated with pressed glass, tableware, and decorative household items.

Each region developed its own aesthetic, influenced by local tastes, technology, and available materials. The aim for ANNAGATE is to offer pieces from every region whenever possible insuring a unique catalog to choose from, every store visit.

Uranium glass and World War II

Production of uranium glass declined sharply during World War II. As uranium became strategically important for military and nuclear research governments restricted access to uranium compounds, restraining access to uranium oxide for glass makers resulting in the ceasing of production in many countries. After the war, uranium glass production never fully returned to its pre-war scale. Changing tastes, regulations, and public perception contributed to its decline.

Some limited production resumed in the post-war years, especially for scientific glass, specialty decorative items and small-scale artisanal glass making. Modern uranium glass exists, but it is typically clearly identified as contemporary and differs in style and context from antique and vintage pieces.