James Apjohn FRS (1 September 1796 – 2 June 1886) was the Irish chemist known for the discovery of new minerals.

James Apjohn (1796-1886) was a renowned and respected chemist and physicist who lived and worked in Dublin during the 1800s.

A mineral from Algoa Bay, South Africa, which proved to be an effloresced manganese alum was analysed and described by Apjohn to great acclaim.

He attended the Tipperary Grammar School for four years before entering Trinity College Dublin in 1813 as a sizar under the tutorship of Rev.

Not only did he qualify as M.D from Trinity but he was also awarded the Cunningham Medal by the Royal Irish Academy for his paper 'Upon a New Method of Investigating the Specific Heat of Gases'.

James Apjohn died in Blackrock, County Dublin on 3 June 1886 at the age of 91.