The SWAN showing is located approximately 20 kilometres north- west of Summerland and 2.4 kilometres west of Darke Lake Provincial Park.
In the mid-1970s, some stripping and sampling was carried out on the showing by Mr. Plank, a local resident. In the late 1970s the property was held by Okanagan Silica Ltd. There are no records of any subsequent property work, bulk sampling or production.
The showing is underlain by the Middle Jurassic Osprey Lake Intrusions; it consists of a quartz-pegmatite body, hosted by an altered, coarse-grained, intergranular quartz monzonite. The pegmatite is exposed in scattered outcrops, road cuts and trenches on a steep northeast-facing slope. The area exposed is approximately 60 by 120 metres with a vertical extent of about 75 metres. The pegmatite is composed of 25 per cent massive quartz, 10 per cent muscovite, 10 per cent feldspar, and the remaining 55 per cent is an intergrowth of quartz and feldspar with small amounts of muscovite.
A chip sample of quartz collected by the Geological Survey Branch analysed 99.54 per cent silica (Open File 1987-15). Muscovite occurs as pockets and seams of fine to coarse-grained pearly white subhedral to euhedral radiating clusters and books. Coarse-grained flakes of muscovite, to 1 centimetre in size, are commonly found with coarse-grained intergrowths of quartz and feldspar. Feldspar is present as orthoclase and albite. Masses of the host intrusive rock are sometimes present within the quartzose mass, peripherally accompanied by malachite and limonite staining.