Vivianite

Part of speech: noun

Definitions

1. A phosphate mineral characterized by its blue-green coloration and notable light sensitivity that leads to a transformation in hue over time
2. A distinctive mineral found in iron-rich deposits that has a striking blue-green appearance and exhibits a color shift when subjected to light exposure
3. A mineral composed of iron and phosphate, which is typically recognized for its vivid blue-green color and tendency to change hue when exposed to light

Etymology: Vivianite is named for Jeffrey G. Vivian, an English mineralogist who identified the mineral in 1817. Mineral names often commemorate the people who first described them, and this one is no exception: the blue-green crystals that Vivian examined were given his name as a lasting record of his work. The name is a plain eponym with no folk story attached. Its only job is to tie the mineral to its discoverer, so the word tells you nothing about the mineral's chemistry on its own; you need the definition for that. Still, it is a neat example of how a scientist's surname can become a permanent part of a technical vocabulary.