 He met with Dolomieu in Laibach in 1784.Among Hacquet's written works is the four-volume "Oryctographia Carniolica", which included a geological and mineralogical study of Carniola, Istria, and surrounding districts.In this work, published in Leipzig from 1778 until 1789, he provided an in-depth report of the Idrija mercury mine, where he worked for some time with the physician and naturalist Giovanni Antonio Scopoli.