Ruby and Golconda

Prospect, Inactive

Commodities and mineralogy

Main commodities Cu
Ore minerals azurite; chalcopyrite; limonite; malachite
Gangue minerals quartz

Geographic location

Quadrangle map, 1:250,000-scale NM
Quadrangle map, 1:63,360-scale C-1
Latitude 64.6814
Longitude -165.4832
Nearby scientific data Find additional scientific data near this location
Location and accuracy This prospect is at an elevation of about 900 feet on the divide between the headwaters of Twin Mountains Creek and Butterfield Canyon. The prospect is about one-quarter mile northwest of the Lilly prospect (NM189). The location is near the center of section 28, T. 9 S., R. 34 W., Kateel River Meridian.

Geologic setting

Geologic description

Mertie (1918 [B 622-I, p. 442]) reported azurite and malachite in fractured quartz on the Ruby and Golconda claims at the head of Twin Mountains Creek. A copper-bearing quartz vein located by Kennecott Exploration Company at the head of Twin Mountain Creek in 1993 is assumed to be the vein described by Mertie. Hummel (1962 [MF 247, locality 9]) reported copper at the nearby Lilly prospect (NM189) but he may have confused the Lilly and Ruby and Golconda prospects because the Lilly deposit apparently does not contain copper (C.C. Hawley, unpub. data, 1993).
The Ruby and Golconda deposit is a concordant quartz vein about 2 feet thick. The vein is coated with limonite and contains less than 2 percent malachite and azurite as fracture coatings and about 1 percent disseminated chalcopyrite in grains less than 0.2 inch across. The quartz strongly resembles limonite-stained sugary quartz boulders found throughout the western part of the Nome district, most commonly in stream float. Such boulders contain sparsely disseminated chalcopyrite and few other sulfide minerals. The concordant nature of the quartz vein at Ruby and Golconda and similar occurrences elsewhere suggests that these copper-bearing quartz veins are very early, having formed essentially by metamorphic processes prior to the main gold-mineralizing events at Nome. This early quartz could correlate with the weakly metallized quartz rods at the upper Butterfield Creek deposit (NM164).
Geologic map unit (-165.485812019639, 64.6806343512235)
Mineral deposit model Concordant copper-bearing quartz vein in schist.
Age of mineralization Pre-Late Cretaceous; possibly as old as early Paleozoic, the protolith age of the enclosing metamorphic rocks.
Alteration of deposit Oxidation.

Production and reserves

Workings or exploration A short tunnel was reported but was not found by Mertie (1918) or by C.C. Hawley in 1993.
Indication of production None

Additional comments

Sometimes confused with the nearby Lilly prospect (NM189).