The Gold Hill claim is underlain by Pennsylvanian and possibly Permian Mount Roberts Formation rocks comprised of a coarse sedimentary breccia that grades to the east into a grayish to green, thinly laminated sandstone that, still farther east, grades into thinly bedded grey siltstone and argillite. A mass of Middle Eocene Tertiary Coryell Intrusions, comprised of syenite to monzonite, intrudes these older rocks; the eastern portion of the claim is reported to be underlain by syenite porphyry.

On the claim, the Mount Roberts bedded rocks strike northwards and dip steeply to the west. The host rock is black argillite with some coarser, banded, brown rock that resembles an ash bed or a tuff. Mineralization consists of a series of quartz stringers or veinlets containing pyrrhotite with some calcite along with the quartz. Drusy cavities are present in the quartz. Arsenopyrite was also reported to occur with the vein pyrrhotite. Disseminated pyrite is also present.

In 1894, 9 tonnes of high grade ore were shipped from a quartz vein and 31,103 grams of silver was recovered.