Adam Seybert (May 16, 1773 – May 2, 1825) was an American politician who served as a Democratic-Republican member of the U.S. House of Representatives for Pennsylvania's 1st congressional district from 1809 to 1815 and 1817 to 1819. He was a faculty member at the University of Pennsylvania and a mineralogist who organized the first mineralogy collection in the United States in the 1790s.

Seybert was born on May 16, 1773, in Philadelphia, Pennsylvania. He graduated in 1793 with a degree in medicine from the University of Pennsylvania. He continued his studies in Europe, and attended schools in Edinburgh, Göttingen, and Paris.^[1] He studied mineralogy at the Ecole des Mines and was the first American to study mineralogy in Germany.^[2] He returned to Philadelphia with a collection of minerals^[3] and worked as a physician for a short time before establishing himself as a "druggist, chemist and apothecary".^[2] He was a faculty member at the University of Pennsylvania.^[4] He was elected as a member of the American Philosophical Society in 1797,^[5] and a Fellow of the American Academy of Arts and Sciences in 1824.^[6]

In 1809, Seybert was elected to the 11th United States Congress as a Democratic-Republican representative for Pennsylvania's 1st congressional district^[7] to fill the vacancy caused by the resignation of Benjamin Say. He was reelected to the Twelfth and Thirteenth Congresses. He was chairman of the United States House Committee on Revisal and Unfinished Business during the Twelfth Congress. He was again elected to the Fifteenth Congress^[1] and served from 1817 to 1819.^[7] He visited Europe from 1819 to 1821 and again in 1824 and settled in Paris, France, where he died May 2, 1825. He was originally interred at Père Lachaise Cemetery in Paris^[1] and re-interred to Laurel Hill Cemetery in Philadelphia.^[8][9]

Seybert established the first mineralogy collection in the United States in the 1790s. The collection contained over 1,725 crystals and rocks. The noted mineralogist, Benjamin Silliman, was known to have traveled to Philadelphia to view the collection,^[10] and have Seybert analyze minerals from Silliman's collection.^[3] In 1812, Seybert sold his mineralogy collection to the Academy of Natural Sciences in Philadelphia.^[11] His political career took priority over his interest in mineralogy, and when Parker Cleaveland wrote to him in December of 1813 with questions on mineralogy, he replied that he had lost interest in the science.^[11]

After Seyberts' death, his mineralogy collection was put on display at the Free Natural History Museum of the Academy of Natural Sciences in Philadelphia.^[10]

The University of Pennsylvania philosophy department named a chair in the department the Adam Seybert Professor in Moral and Intellectual Philosophy. The chair was funded by Adam's son, Henry Seybert. The duties of the chair included hosting the Adam Seybert committee which investigated the possibility of the spirit world. The committee met from 1883 to 1887 but was unable to discover any evidence and subsequent holders of the chair were freed from continuing the investigations.^[4]

• Experiments and Observations on Land and Sea Air, Transactions of the American Philosophical Society, 1799
• An Inaugural Dissertation: Being an Attempt to Disprove the Doctrine of the Putrefaction of the Blood of Living Animals., Philadelphia: T. Dobson, 1793
• Statistical Annals: Embracing Views of the Population, Commerce, Navigation, Fisheries, Public Lands, Post-Office Establishment, Revenues, Mint, Military and Naval Establishments, Expenditures, Public Debt and Sinking Fund of the United States of America, Philadelphia: Thomas Dobson & Son, 1818