coppery

kuparinvärinen Resembling the metal copper, especially in color.
2002, E. P. Anshutz, New, Old and Forgotten Remedies (page 380)

That night I dreamed I had a very disagreeable taste in my mouth, which caused me to spit all the time. I awoke and found my mouth full of saliva, with a coppery taste, and sure enough, I was obliged to spit.

Venetian women who wanted coppery hair colors applied bleaching mixtures, such as one that contained alum, sulfur, soda, and rhubarb. Then they sat in the sun, where heat produced a chemical reaction that developed the color.