Unfortunately Sterba and Lorenz (2005) overlooked some of the relevant literature before describing the species represented by your shell (and its generic-level placement) as new. Refer to the webpage
http://www.jaxshells.org/riceo.htm and Lee (2004). The correct name is Olivellopsis simplex (Pease, 1868).
Lee, H. G., 2004. What is a Rice Olive anyway? Shell-O-Gram 45(5): 4-6. Sep.-Dec.
http://www.jaxshells.org/sepdec04.pdf.
Sterba, G. H. W. and F. Lorenz, 2005. Olivella (Janaoliva) amoni, a new subgenus and species from the Bismarck Archipelago and Indonesia (Mollusca: Gastropoda: Olivellidae). Visaya 1(3): 43-46. Jan.
Harry Lee