Pandoc Diamond Symbol Not Working With Subscript

I’m trying to convert a book to word format (or at least get a passable first attempt) using pandoc and the book frequently uses the symbol Diamond in equations. However, pandoc’s output gives garbage whenever that symbol is subscripted.

Here is test code of a file and a screen shot of the resulting output

documentclass[11pt,leqno]{article}
usepackage{amsmath,amssymb}

begin{document}

( Diamond phi ) 


( Diamond_{phi} psi iff Box_{phi} phi ) 

end{document}

And here is what is produced after running: pandoc test.tex -o test.docx (latest word for OS X)

Note that it works fine without a subscript Is there any way to redefine/replace Diamond with some other symbol that pandoc will handle? Other solutions?

(diamond seems to work better but produces much too small a symbol).