Adolarius Jacob Forster (1739–1806) was a Prussian mineralogist and dealer in display specimen minerals.
Adolarius Jacob Forster began dealing in mineral specimens around 1766, at the age of 27.
Auction catalogues for sales in Paris were written by Romé de l'Isle.
He was related to Johann Georg Adam Forster and Johann Reinhold Forster and his sister married the London dealer naturalist George Humphrey at St-Martin-in-the-Fields, London on August 16, 1768.
In 1802 Forster sold a collection to the museum of the St Petersburg Mining Institute, under the auspices of the Emperor of All Russia Alexander I.