The use of uranium as a colorant in glassmaking dates back to ancient Roman times, with a mosaic containing yellow glass with 1% uranium oxide discovered in a villa from 79 AD.1 However, uranium glass as we know it today first appeared in the 1830s, with Josef Riedel often credited as the inventor. He named the yellowish-green and yellow varieties "Annagrün" and "Annagelb" respectively, after his wife Anna Maria.23

Riedel's factory in Bohemia produced uranium glass between 1830 and 1848. The popularity of uranium glass grew throughout the 19th century as more factories began production, including Whitefriars Glass Company in London which helped bring it to the mass market in the 1880s.13 Uranium glass was used to create a wide range of items during this time, from decorative pieces to tableware and jewelry.3

The fluorescent glow of uranium glass is caused by the presence of uranium oxide in the glass mixture. When exposed to ultraviolet light, the uranium atoms absorb the high-energy UV photons, becoming excited. As the atoms return to their ground state, they emit lower-energy photons in the visible spectrum, primarily in the green and yellow wavelengths, creating the characteristic glow.12 The uranium content in the glass is typically low, around 2% by weight, but can range up to 25% in some older pieces.3 While the radioactivity of uranium glass is generally considered low and safe for display or use, caution should still be exercised in handling, and it is not recommended for serving food or drink due to the risk of ingesting small glass fragments containing uranium.34

Prior to the discovery of radioactivity in the late 19th century, uranium found early industrial use as a colorant in the production of glass and ceramics. Uranium oxide was added to glass mixtures before melting to impart yellow, green, and even opaque white hues to the finished products.12

Uranium glass became especially popular in the mid-1800s for the manufacturing of decorative household items like vases, bowls, and candlesticks. The vibrant, fluorescent colors made possible by uranium were prized for their unique beauty.3 Some of the first major producers included Franz Xaver Riedel's glassworks in Bohemia and the Baccarat company in France, which developed an opaque green uranium glass known as "chrysoprase" in the 1840s.13

In addition to purely decorative objects, uranium glass also found use in the production of more functional items like custard cups, butter dishes, and even glazed ceramic floor tiles during its peak of popularity in the late 19th and early 20th centuries.45 The widespread industrial applications of uranium in the decorative arts during this time helped establish it as an important material long before its radioactive properties were fully understood or applied to other uses.