A past question from NO QUARTZ, the free daily watch quiz. The answer is highlighted below.

Question 2·Multiple choice

In 1949 Panerai registered 'Luminor' as the name of a new self-luminous substance, replacing its earlier Radiomir. What was Luminor based on?

  • A.Radium bromide
  • B.TritiumCorrect answer
  • C.Promethium-147
  • D.Strontium aluminate

The story behind it

Radiomir, from 1916, was a radium-based powder; Luminor swapped radium for tritium, a hydrogen isotope with much lower radioactivity. The name began as a lume, not a watch, which is why 'Radiomir' and 'Luminor' now label case families rather than paints.

From NO QUARTZ Ref. NQ0006, the puzzle for Sept 28, 2026.

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