I reviewed a number of TTFs with “Character Map” Windows utility, and it seems #9723 (U+25FB) glyph is quite rare in TTFs. I have only found it in DejaVu family of fonts.

So try to modify the font-family directive like that:
“font-family: Verdana,Geneva,’DejaVu Sans’,Arial,Helvetica,sans-serif”

(Make sure DejaVu font is installed and indexed, and do not forget to substitute ‘=’ with ‘:’ in the property definition)