What radioactive element was commonly used in luminous paints before the mid-to-late 1960s?
Answer
Radium
Radium, specifically Radium-226, was historically used in luminescent materials like watch dials, causing them to glow via natural radioactive decay.

Related Questions
What process is responsible for the safe, modern glow emitted by contemporary glow-in-the-dark items?What radioactive element was commonly used in luminous paints before the mid-to-late 1960s?What is the key non-toxic chemical compound responsible for the strong, long-lasting glow in modern stars and paints?What type of ionizing radiation does Radium-226 emit that poses a health risk?What is the fundamental difference between how modern phosphorescent stars and historical radium objects derive their energy?How far does the text state alpha radiation emitted by radium can travel externally?If a glow item glows continuously in total darkness without ever being exposed to light, what should a consumer suspect?What specific packaging claim indicates a modern, safe glow product?According to the text, how long might a high-quality strontium aluminate star retain a visible glow after a full charge?Why did factory workers who painted radium watch dials face severe danger?