- , revised by Anita McConnell
Allan, Thomas (1777–1833), mineralogist, was born at Edinburgh on 17 July 1777, the eldest of ten children born to Robert Allan (1745–1818), a partner in Allan and Stewart, bankers and merchants, and proprietor of the Caledonian Mercury, and his wife, Anne, daughter of William Learmonth. After education at Edinburgh high school he entered his father's bank, but took to scientific pursuits from his childhood. At the peace of Amiens he visited Paris, made scientific acquaintances, and began a mineralogical collection in Dauphiné. He married, on 1 January 1806, Christian (1778–1817), daughter of George and Juliet Smith of Burnhall, co. Durham. They had five children; Christian died at Turin, Italy, on 14 May 1817.
In 1808 Allan published an Alphabetical list of the names of minerals at present most familiar in the English, French, and German languages and he was the reputed author of a Sketch of Mr. Davy's Lectures in Geology, from Notes Taken by a Private Gentleman (concerning Humphry Davy), which appeared about 1811. He afterwards travelled in Ireland and England; in 1812 he visited the Faeroe Islands, and sent an account of their mineralogy to the Royal Society of Edinburgh. In 1811 the Bavarian mineralogist Karl Giesecke shipped to Denmark a collection of minerals, formed during six years' residence in Greenland. The ship was captured by a French privateer and retaken by an English frigate, and the boxes, their contents considered to be of little value, were sold at Leith to Allan for £40. They contained a quantity of the rare mineral cryolite, worth some £5000, and a new mineral, later named, after the purchaser, allanite. Allan discovered the identity of the collector and the provenance of the samples only in 1812, and was pleased to meet Giesecke when he returned to Leith with a fresh collection from Greenland.
The following year Allan supported Giesecke's successful application for the professorship of mineralogy at Dublin. Allan continued to increase his collection, with the assistance of W. Haidinger, a German geologist, until it became the finest in Scotland. Allan was an admirer of Hutton, and published papers on his theories in the Edinburgh Transactions. He also wrote the article 'Diamond' for the Encyclopaedia Britannica. He was elected to the Royal Society of Edinburgh in 1805, and to the Royal Society of London in 1815. He was a public-spirited citizen, filled many municipal offices, and was a liberal contributor to Edinburgh charities. He took over from his father as the proprietor of the Caledonian Mercury. He died of apoplexy on 12 September 1833, at Linden Hall, Northumberland, and was buried at St Cuthbert's churchyard, Edinburgh. His eldest son, Robert Allan (1806–1863), advocate and banker, also took an interest in mineralogy. He accompanied his father on a geological excursion to Cornwall and travelled widely in Europe. His Manual of Mineralogy (1834) was illustrated by his own fine drawings of crystals.
- W. V. Farrar, ‘Thomas Allan, mineralogist: an autobiographical fragment’, Annals of Science, 24 (1968), 115–20
- A. L. Reade, ‘Pedigree XVIII: Anderson of Clough ... with Reid, Allan’, The Reades of Blackwood Hill in the parish of Horton, Staffordshire: a record of their descendants (privately printed, London, 1906), 65–9
- GM, 1st ser., 103/2 (1833), 382
- Burke, Gen. GB (1846–9)
- The Scotsman (18 Sept 1833)
- private information (2004); (2015) [D. Radcliffe]
- NHM, catalogue of mineral collection
- NHM, notebooks
- H. Raeburn, portrait, 1801
- H. Raeburn, portrait, 1805
- portrait, National Museum of Scotland
Wealth at Death
£2190 5s. 6d.—Robert Allan: confirmation, 1863, NA Scot., SC 70/1/118