Thomas Diamond was born about 1800 in Bristol, UK. At the age of 19 he was sentenced to seven years transportation for stealing 120 yards of cloth. He arrived in Sydney, Australia, in 1821 on board the ship Hindostan.
Shortly after completing his sentence in 1828, he married Mary Buckley, a 20 year old convict woman, recently arrived from Limerick, Ireland. Mary had also been sentenced to seven years transportation for stealing a cloak.
The couple lived in Sydney for a few years before moving to the Goulburn district where Thomas carried on his trade as a stone mason. Thomas must have died about 1850, as Mary married Joseph Forman at St Saviour's Cathedral Goulburn on 16 February 1852.
Mary was committed to Tarban Creek Hospital in 1857 for her own safety, and she remained at Tarban Creek and later Newcastle Hospital till her death in 1876.