The Nighthawk showing occurs on the west bank of the Tulameen River, 9.5 kilometres west-northwest of Princeton.
A stock of fine to medium-grained granodiorite and quartz diorite intrudes fine-grained amygdaloidal andesite with minor andesitic tuff and agglomerate of the Upper Triassic Nicola Group. The stock trends northwest along the Tulameen River for at least 300 metres. A similar stock hosts the Tulameen showing (092HSE111) across the river to the south.
The andesitic rocks are extensively chloritized near the intrusion. Minor epidote is also present. The granodiorite shows weak epidote and chlorite alteration.
Pyrite is the most common sulphide, and is concentrated in and around the intrusion as disseminations and in massive veins and shears. Chalcopyrite occurs along shears, fractures and in quartz veins in the altered andesite near the stock. Minor chalcopyrite is also found in quartz veins cutting granodiorite. Sparse molybdenite is disseminated in andesitic tuff just east of the intrusion.