Stewart, of Glenormiston, Perthshire, Scotland, he purchased the Glenormiston property.
The partnership, which was highly remunerative after 1846, continued until 1868, when the property was divided.
Black bought Gladstone's portion, now known as Mount Noorat, and resided on it until his death on 15 May 1880.
Black, who married Miss Grace Greenshiels Leadbetter, represented the Western Province from February 1859 to May 1880 in the Legislative Council, and was also a magistrate for the southern bailiwick.
As a politician he was a staunch Conservative, and opposed the introduction of free education.