Fred Stewart was a typical canny Aberdonian, born and bred. He read Geology at Aberdeen University and after postgraduate research at Emmanuel College, Cambridge became a mineralogist with ICI (1941-43). A lectureship in Geology at the University of Durham (1943-56) was followed by his appointment to the Regius Chair of Geology and Mineralogy in the University of Edinburgh in 1956 from where he retired in 1982.
Rocks and minerals in whatever shape or form fascinated Fred Stewart from his schooldays onwards. His early researches were devoted to the igneous rocks in Skye and Belhelvie in Aberdeenshire. His work on the Belhelvie complex was published in the Quarterly Journal in 1947. His wartime translation to ICI confronted him with a very different set of problems associated with the genesis and distribution of the economically valuable salt deposits in Yorkshire. These Permian water-soluble rocks were extremely difficult to thin-section and the minerals themselves were diagenetically complex. He was able to find potassium salts, strategically vital to the Allied war effort, because the German Stassfurt deposits were no longer available. His meticulous work on evaporite deposits, published in the Mineralogical Magazine, was recognised by the award of the Lyell Fund by the Geological Society in 1951 and the Mineralogical Society of America award in 1953.
Fred Stewart described himself at the time as a simple petrological policeman looking for places to put his large feet. The US Geological Survey published his major review paper on salt deposits in 1963. He later returned to Scottish rocks with work in the NE of Scotland and the volcanic complexes of the Scottish islands. He was elected a Fellow of the Royal Society of Edinburgh in 1961 and the Royal Society of London in 1964 and awarded the Society’s Lyell Medal in 1970. He was knighted in 1974.
From his appointment in 1956 Stewart trebled the size of the Edinburgh department and generated enough funding to build and equip a major experimental petrological laboratory. That laboratory was chosen by NASA for the analysis of lunar samples under vacuum to simulate conditions on the Moon.
Stewart became a member of the Council for Scientific Policy in 1967 and for the next 12 years spent much of his time in London as a scientific statesman. He was appointed Chairman of the Natural Environment Research Council in 1971. Both friends and opponents quickly discovered that his somewhat unkempt look and friendly unassuming manner masked a brilliant intellect and formidable incisiveness in debate. Fred Stewart, mineralogist, was also a most competent natural historian. He had studied zoology for three years at Aberdeen before electing to read honours in geology and his father, an enthusiastic bird photographer, had encouraged his keen interest in ornithology.
In 1974 he became chairman of the Advisory Board of Research Councils with (at that time) an annual budget of some £500 million. During his six years of office he served under four Secretaries of State including Mulley, Prentice, Thatcher and Williams. He was a Trustee of the British Museum (Nat. Hist.) from 1983 until 1987.
Fred Stewart retired in 1982 to live in the village of Loch Awe in Argyll. He was a keen salmon fisherman but on poor days for fishing he hunted for fossil fish from the Old Red Sandstone and minerals. Eventually he discovered the largest sapphire ever found in Scotland. He had a great love for the Scottish hills and occasionally he and his wife were to be found strolling on the mountain peaks through the simple expedient of hiring a helicopter.
Fred Stewart married Mary Stewart (née Rainbow) in 1945. She has a highly successful career as a writer and survives him. There were no children of the marriage.
Gordon Y. Craig