The paper provides information on chemical composition of a fossil resin called duxite. Methods of elemental analysis, microscopy,
chromatography, and infrared spectroscopy were used to analyse samples mostly found in mineralized tree trunks and deposited
in the Miocene sediments of the Most and Sokolov basins. All studied samples have shown similar chemical compositions, rich in
sesquiterpenes (α-cedran, cuparene) and diterpenes of abietane, pimarane, and dehydroabietane structures. The infrared spectra
have confirmed an aromatic character of duxite and higher maturity of the samples. The identified compounds indicate that the
source of duxite was resin from conifer trees of the Cupressaceae family. Differences in composition among individual samples
can be attributed to different conditions during fossilization and post-deposition history of the material, as verified by laboratory
experiments. A unique feature of duxite is a low softening point and its excellent solubility in organic solvents, which supports its
nonpolymerized structure, so unusual for fossil resins.