magnesium

noun

1. (uncountable)The chemical element with an atomic number of 12. It is a light, easily flammable, silvery-white alkaline earth metal.

   “1999, Chapter 1 "Barrens" Cryptonomicon by Neal Stephenson The building looked only like a wall glowing in the firelight, but sometimes a barrage of magnesium blue light made its windowframes jump out of the darkness.”

   “A sample of carbon removed from the ocean in the solid form of calcium carbonate and magnesium hydroxide from UCLA's SeaChange program -- now known as Equatic -- in 2023.”