The Diocesan Coat-of-arms are green with a gold sheaf of wheat enscribed with a white disc on which the Greek letters Alpha and Omega are written. This is in allusion to the fertile Darling Downs where wheat is a major crop.
The letters Alpha and Omega refer to the fullness of God in Jesus Christ, and are from the Book of Revelation: "I am the Alpha and the Omega" says the Lord God, who is and who was and who is to come, the Almighty. (Rev. 1:8) The disc with the the letters Alpha and Omega indicates the relationship between the wheat and the Sacrament of the Eucharist.
The serrated division between the upper and lower parts of the shield alludes to the Dividing Range which is a feature of the Cathedral city. The upper section is white with a red diagonal cross, being the cross of St. Patrick, the patron of the Cathedral.