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).