The Rain (Zinc Vein) occurrence is located approximately 850 metres southwest of the Junction of Kains Creek and the Nahwitti River.

Regionally, the area is underlain by northwest-trending belts of basaltic volcanics and carbonate sedimentary rocks of the Upper Triassic Karmutsen and Quatsino formations (Vancouver Group) and mafic volcanics and sediments of the Upper Triassic to Lower Jurassic Bonanza Group (Holberg volcanic unit, Nahwitti River wacke and Parson Bay Formation). These volcanic and sedimentary rocks have been intruded by granodioritic rocks of the Early to Middle Jurassic Island Plutonic Suite.

Locally a vein of sphalerite with minor pyrite and chalcopyrite is found south of a monzonite or possibly dioritic intrusive. The vein averages 0.60 metre in width and has a surface strike length of 27 metres. The attitude of the vein conforms to that of the Bonanza sediment, striking 100 degrees and dipping 40 to 60 degrees south. Bonanza limestone is found in the footwall at surface, whereas drilling encountered Bonanza sediments in the hangingwall and siliceous skarn in the footwall.

In 1972, drilling intercepted stringers of sphalerite between 18.3 and 21.3 metres depth that assayed up to 11.2 per cent zinc over 0.3 metre, whereas a 0.60-metre chip sample at surface assayed 6.4 per cent zinc and 29.5 grams per tonne silver (Assessment Report 4180).

In 1988, a channel sample (09293) assayed 33.60 per cent zinc and 18.5 grams per tonne gold over 0.3 metre (Assessment Report 17445).

The area has been explored in conjunction with the nearby Dorlon (MINFILE 092L 076) occurrence since the early 1930s. In 1966, Giant Explorations Ltd. completed a program of geological mapping and geochemical sampling on the area as the HPH claims. During 1969 through 1972, Giant Explorations Ltd. completed programs of soil sampling and ground and airborne geophysical surveys on the area.

In 1981, the area was prospected as the JR claims. During 1987 through 1991, Hisway Resources Corp. completed programs of geological mapping, ground geophysical surveys, geochemical sampling and six drillholes, totalling 381.5 metres, on the area. In 1992, Cameco Corporation completed a program of rock and soil sampling, geological mapping and ground geophysical surveys on the area.

In 2017 and 2018, Precipitate Gold Ltd. completed programs of rock and soil sampling, gravity surveys and prospecting on the area as the Island Zinc property.