The Royal Hawaiian Mint website indicates that the 1991 Royal Hawaiian Platinum Hapaumi Puela 1/10 Oz Platinum was never issued and only 23 were struck.
However, if you know your RHM database and are familiar with the issued sets… this coin was part of the Hawaiian Regency Collection set.
Mintage is now 923. (900 issued in sets and 23 issued individually)
My May 26, 2013 discusses the Hawaiian Regency set.