The Sun occurrence is located on Red Mountain, about 26 kilometres north of the community of Atlin.

The area is underlain by quartz monzonite of the Middle Jurassic Fourth of July Creek batholith (Three Sisters Plutonic Suite). A northeast trending kaolinite-sericite alteration zone, developed in the intrusion, is approximately 23 metres wide and 123 metres long. Diorite dikes have cut the intrusion both before and after the alteration event.

Molybdenite occurs as scattered flakes and books of flakes concentrated on the northwest and west side of the alteration. Galena veins occur associated with quartz veins. Malachite stains were also reported.

In 1969, the showing was originally staked as the Sun 1-6 claim group by C. Aspinall for Canadian Johns-Manville Co. Ltd. who conducted geological reconnaissance, and soil and talus-fine sampling programs on the 1372-metre contour around Red Mountain and the 1311-metre contour on the north slope of the Red Mountain ridge. The Red Mountain area was investigated due to a distinctive iron oxidized stain in addition to a white alteration zone located on its south slope.

In 1973, Canadian Johns-Manville completed 3.4 kilometres of a ground magnetometer survey.

In 1980, the Red 1 claim was staked for Placer Development Limited who established a grid (4.9 kilometres) and conducted geological mapping, a VLF-EM and magnetometer survey, and collected 121 soil samples for analysis.