[1][2][3][4] Joseph Paxson Iddings was born in Baltimore, Maryland on January 21, 1857, the son of a wholesaler in Philadelphia.

[5] He received a master's degree from Yale College's Sheffield Scientific School in 1877[6] and then studied analytical chemistry at the University.

He spent 1879-1880 at the University of Heidelberg, where he conducted petrographic research under the direction of Karl Rosenbusch.

[6] Beginning in 1892, he lectured at the University of Chicago, where a Department of Petrology, the first of its kind in the world, was created especially for him.

He died unmarried and childless at his home in Sandy Spring, Maryland on September 8, 1920, from chronic nephritis.