The Treasure Mountain region is underlain by northwest striking, moderate to steeply southwest dipping volcanic and sedimentary rocks of the Lower-Middle Jurassic Dewdney Creek Formation (Ladner Group) and Lower-Upper Cretaceous Pasayten Group, intruded by numerous dikes and sills. The Dewdney Creek Formation comprises volcanic rocks and a minor amount of sediments and consists of tuff, breccia and agglomerate with interbedded argillite and conglomerate. The Dewdney Creek Formation is considerably altered; pyrite is commonly present and many outcrops are rusty. The Pasayten Group includes predominantly arkose, argillite and conglomerate. Locally, the two sequences are separated by a northwest striking, northeast dipping fault, but in large part are conformable.

Mineral occurrences in the area are hosted in the Treasure Mountain fault and in and near subsidiary faults, and comprise one or more quartz-carbonate veins or stringers that branch and split and vary considerably in width and attitude (see Treasure Mountain, 092HSW016).

The Morning Star occurrence is underlain by northwest striking, southwest dipping Dewdney Creek Formation andesite and tuffaceous rock. A fracture zone hosts an oxidized quartz-calcite stringer vein zone that varies from a few centimetres to 45 centimetres in width. The zone strikes 075 degrees and dips 45 degrees south and is mineralized with galena, sphalerite and pyrite with manganese oxide staining. A second stringer vein zone outcrops 22 metres southwest of the first and strikes 045 degrees with 80 degree south dips. This zone is 60 centimetres wide and is sparsely mineralized.

Underground development along the fracture zone revealed that it is very narrow and sparsely mineralized with the exception of a 3-metre section where the zone is 60 centimetres wide and mineralized with galena, sphalerite, tetrahedrite and pyrite in a gangue of gouge and silicified and brecciated andesite wallrock. Crosscutting intersected another zone (apparently a widened continuation of the first) 7.6 metres wide containing three mineralized fractures, each 60 centimetres wide, separated by bands of altered andesite. The fractures contain sphalerite, galena and pyrite in a gangue of brecciated wallrock.

A grab sample of ore in an opencut above the adit portal assayed 1.37 grams per tonne gold, 2571 grams per tonne silver, 42 per cent lead and 8 per cent zinc (Minister of Mines Annual Report 1927, page C255).