quicksilver has definitions from the field of chemistry
1
[ adjective ] liable to sudden unpredictable change

Examples

"erratic behavior" "fickle weather" "mercurial twists of temperament" "a quicksilver character, cool and willful at one moment, utterly fragile the next"

Used in print

(Robert A. Futterman, The Future of Our Cities....)

If anything may be predicted in the quicksilver world of retailing , it seems likely that the suburban branch will come to dominate children 's clothing ( taking the kid downtown is too_much of a production ) , household gadgetry and the discount_business in big-ticket items .

Related terms

changeable

2
[ noun ] (chemistry) a heavy silvery toxic univalent and bivalent metallic element; the only metal that is liquid at ordinary temperatures
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