Never tried it, but one recipe I've seen states you can heat a sample with an equal volume of table salt @1500F for 1 hour, then digest in distilled water.
Add a saturated solution of ammonium nitrate to the filtered solution:
Au precipitates as native gold;
Rh forms a HCl soluble orange-yellow precipitate;
Ir forms a yellow salt very slowly after boiling;
Os precipitates as a red salt.
Perhaps I can get my hands on a known Ir sample and post a video of these test results on my website.
Steve