These are my grandfather's sgt. chevrons. The button, which I've recently been told is black because he was in mourning, has the RIR harp on it and appears to be of gutta percha (not quite rubber). The button and chevrons have always been displayed as such as long as I have known of them.

Front || This envelope was among my grandfather's effects. The postmark is very faint but appears to be dated 1919. It has his Regimental number on it 20238 and is addressed to 20238 Sgt. Robert Beatty Irish Rifles 25 Eglantine Avenue Belfast

Certificate of Employment during the war. Undated. My grandfather's surname is misspelled Beattie (it's Beatty). Regimental #20238 Rank Sgt. Regt Royal Irish Rifles Unit 3rd Batt.