After examining this 10 mm coin I can say that it is not issued from the Royal Hawaiian Mint (no RHM hallmark). However, the Princess portrait and dolphin designs are similar to those struck by the RHM. There is no rim damage to indicate it was a ex-jewelry piece.
This coin has the triangle circle B hallmarks (design by Bernard von NotHaus) on the reverse. The B is within a circle and within a triangle.
Under 60X magnification, it can bee seen that the B within a circle and within a triangle is present.
The presence of two triangle circle B hallmarks seems odd.
Upon closer examination it was determine that the right hallmark has an incuse circle and B. While the left has a relief (raised) circle and B.
This maybe a prototype (pattern) coin stuck by Bernard von NotHaus or by a mint he was associated with (after his time at the RHM).