the.com/impurity
The uninvited guest that somehow becomes the whole personality of the party.
means A trace of something foreign mixed into a substance that is supposed to be pure — the stuff that shouldn't be there but is.
from From Latin impuritas, built from the prefix in- ('not') plus puritas ('purity, cleanness'), itself from purus ('clean, pure'). Purus is an old Latin word of uncertain deeper origin — possibly related to the idea of being 'cleared' or 'purged' — but the trail goes cold before that. The word entered English in the 1500s pretty much ready-made from Latin, carrying its built-in grammar of negation: purity, plus the 'not' that ruins it.
- semiconductors
- doped impurities are what make transistors work at all
- gemstones
- flaws in corundum literally produce rubies and sapphires
- wine
- trace compounds called congeners are why cheap booze gives worse hangovers
- metallurgy
- carbon impurity turns soft iron into hard steel