Display unicode triangles (arrows) in Android -

i've seen following question (javascript encoding question) unicode triangles (arrows) displayed. in android 4.4.4 i've tried use \u25b2 , \u25bc in alert dialog's radio group list, these arrow characters aren't displayed. \u25b4 , \u25be arrows work these arrows big. need use \u25b2 , \u25bc. i've downloaded app "unicode map" google play , these characters not shown well. limitation in android version? i've tested in android 5.0.2 , works.

thank you.