Uranium glass

[1][2] First identified in 1789 by German chemist Martin Heinrich Klaproth, uranium was soon being added to decorative glass for its fluorescent effect.

Otherwise, modern uranium glass is now mainly limited to small objects like beads or marbles as scientific or decorative novelties.

The term is sometimes applied to other types of glass based on certain aspects of their superficial appearance in normal light, regardless of actual uranium content which requires a blacklight test to verify the characteristic green fluorescence.

[10][11] Starting in the late Middle Ages, pitchblende was extracted from the Habsburg silver mines in Joachimsthal, Bohemia (now Jáchymov in the Czech Republic), and was used as a coloring agent in the local glassmaking industry.

The first major producer of items made of uranium glass is commonly recognized as Austrian Franz Xaver Riedel, who named the yellow (German: Gelb) and yellow-green (German: Gelb-Grün) varieties of the glass "annagelb" and "annagrün", respectively, in honor of his daughter Anna Maria.

At the end of the 19th century, glassmakers discovered that uranium glass with certain mineral additions could be tempered at high temperatures, inducing varying degrees of micro-crystallization.

During the Depression years, more iron oxide was added to the mixture to match popular preferences for a greener glass.

[13] This material, technically a glass-ceramic, acquired the name "vaseline glass" because of its supposedly similar appearance to petroleum jelly.