The Officer of the Order of Australia is awarded for distinguished service of a high degree to Australia or humanity at large. The medal of the Officer of the Order of Australia is a badge with a gold-plated silver insignia of the Order in the centre. The central insignia is circled with blue enamel edged in gold and is inscribed with the word ‘Australia’ in gold capital letters. The circle also contains two gold sprigs of mimosa. The insignia is ensigned with the Crown of St Edward in full colour. The medal is hung from the ribbon of the Order. It is royal blue with a central band of mimosa blossoms.