Brownell  writes: The current arms first adopted in 1886, and granted by the College of Arms under Letters Patent dated 12 August 1949. The blazon reads:
Argent on a Cross Gules a Sword wavy proper in the first quarter an Anchor Sable.
The Cathedral Church in Grahamstown is now dedicated to St Michael and St George and these arms comprise the sword of the Archangel Michael and the Cross of St George. The anchor links these arms to those of the Metropolitan See of Cape Town.
These arms were taken into use in 1853, and probably in use until 1886. The blazon reads:
Argent, a saltire Gules, over all an anchor Anchor Sable.
The saltire, or St Andrew’s Cross, in this early version of the arms, commemorates the founding of the Diocese, with that of Natal, on St Andrew's Day 1853. It is, however, in the colours of the cross of St George to whom the Cathedral was then dedicated. The anchor links the arms to those of the Metropolitan See.
Brownell notes an early variant of the arms shown above which may be blazoned:
Azure, a saltire Gules, over all an anchor proper.
The blue field in this version of the Diocesan arms is similar to that of the old See of St Andrew's and, no doubt, was intended to allude to the founding of the Diocese on St Andrew’s Day 1853.
The saltire is, however, in the colour of the cross of St George to whom the Cathedral was then dedicated. The red saltire on a blue field contravenes the heraldic colour rule that tincture should not be placed upon tincture nor metal on metal. The reason for alternating metal and colour in heraldry is a sound one, since it ensures contrast and facilitates easy identification.
Note that in this version the anchor is proper – that is to say, it has a wooden stock, while the rest of it is metallic.