Watson was then commissioned in 1804 to work on the rest of Georgiana's collection, the Chatsworth Mineral Collection, adding a considerable number of items during this time and further refining his understanding of the different types of rock and minerals and their relationships.
Watson kemudian ditugaskan sejak 1804 untuk seluruh koleksi Georgiana, Koleksi Mineral Chatsworth, menambahkan sejumlah besar item waktu itu dan menyempurnakan pemahamannya tentang berbagai jenis batuan dan mineral dan hubungan di antaranya.