In recent years, the scientific community has accumulated a wealth of new data on diamond formation, prompted by developments in experimental and microanalytical techniques including geochronology, high-resolution imaging and diffractometry. A shift of diamond production from exhausted old mines to new pits in Siberia, Canada, Africa, and India has provided geoscientists with many new suites of mantle samples available for research. The session will present recent studies on diamonds, their inclusions, diamondiferous xenoliths and massifs. We invite contributions that address diamond formation in general as well as contributions that characterize regional diamond suites. The session is expected to focus on : 1) petrology of diamondiferous xenoliths, diamond-bearing domains in ultramafic massifs, UHP terrains and other unconventional source rocks; 2) experimental reproduction of diamond formation in the mantle; 3) mineral and fluid inclusions in diamond; 4) the mineralogy of diamond as a key to its genesis; 5) the timing of diamond formation relative to the timing of mantle metasomatism and kimberlite generation; 6) advancements in the scientific paradigm of diamond exploration.