iridize

from The Century Dictionary.

• To make iridescent, purposely or by the action of slow decay. See iridescent glass, under iridescent.
• To cover with iridium; tip with iridium.

from the GNU version of the Collaborative International Dictionary of English.

• transitive verb To point or tip with iridium, as a gold pen.
• transitive verb To make iridescent.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• verb transitive To point or tip with iridium.
• verb transitive To make iridescent.