Looks like my Immortality, how tall is yours?

Just measured it.... right at 30".

I don't think it is..the beard looks yellow. Immortality has a white beard.
IMMORTALITY
(L. Zurbrigg, R. 1982) Sdlg. P 33 Alba. TB, 30" (76 cm), M & RE (summer and fall in VA)
Ruffled pure white; white beard; slight sweet fragrance.

Too often registered descriptions are skimpy.

How do you know for sure? Most of the descriptions I've read say it has a yellow beard. If it's not Immortality what do you think it could be?

The description I gave came directly from the America Iris Society checklist. There are several white iris with yellow beards that are re bloomers..Have you got another picture with a closer view of the iris?? Your best bet would be to buy a start of Immorality from a reputable grower plant it side by side and only then can you tell if it is or not..

Zurich and Hi Ho Silver but the last one has more yellow markings at the hafts..are both white rebloomer with yellow beards.

IMMORTALITY is a re Bloomer. Does it re bloom?

Your best bet would be to find Immortality and grow it side by side with your unknown.. If they bloom at the same time, same height etc, then more than likely it is IMM