Mysteries of vernacular:
Jade,
a hard, typically green stone.
Until relatively recently,
gemstones were believed
to have magical, medicinal properties,
and nothing was more effective
at treating a kidney disorder than jade.
In the 16th century,
the Spanish returned from the New World
with the mineral in their cargo holds
and christened it, "piedra de la ijada,"
or loin stone.
It quickly became popular throughout Europe,
both as a cure for internal ailments
and as a decorative ornament
and was renamed jade by the French,
a word that was borrowed by the English
and remains in use to this day.
In the 19th century,
French mineralogists discovered
that jade was being used
to describe two distinct minerals:
jadeite, which takes its name from jade,
and the more common nephrite,
the root of which is the Greek word nephros,
meaning kidney.
In addition to describing these two minerals,
jade also has an English homonym.
With roots that predate the popularity
of the lustral gemstone,
jade was used to refer to
either a disreputable woman
or a broken-down horse.
Thus, the word jaded, meaning worn out
or lacking enthusiasm,
has nothing to do with the gemstone,
and instead, comes from the archaic,
equine-related definition.