The Ruby Mountains of northeastern Nevada consist of an uplifted core of metamorphosed rock intruded by a number of younger granitic plutons. The Ruby Mountains are a relatively young range. They were formed a mere 20 million years ago during the Miocene Epoch. Named for the small ruby-red garnets that clogged the pans and sluice boxes of early prospectors, the range is known for its spectacular glacial topography.
The southern portion of the Ruby Mountains consists of an uplifted core of ancient Precambrian to lower Paleozoic carbonate rocks and minor clastic sedimentary rocks intruded by a mid-Tertiary pluton composed of mostly quartz monzonite and granodiorite. The Tertiary intrusion is fairly large with an outcrop area of approximately 50 square miles. It covers an area extending from Gilbert Creek (located just east of Jiggs) southward to the Pearl Creek area.
The remainder of the southern end of the range consists mostly of early Paleozoic limestones and dolomites with minor amounts of quartzite, siltstone, and shale. A small wedge of Devonian-Mississippian shale, limestone, and siltstone occurs along the southwestern edge of the range between Cass House Creek and Sherman Creek.
The southern end of the Ruby Mountains is cut by a number of small faults, most of which trend roughly north-south. The ancient Cambrian-Ordovician limestones and dolomites harbor most of these faults.
Mineralization in the Ruby Mountains is weak and consists of small precious and base metal deposits hosted in quartz monzonite intrusions or in the limestones surrounding them. In the Bald Mountain District, the veins were gold and silver-bearing. In the Ruby Valley District they were lead, zinc, silver, and copper-bearing. The Valley View District contained small tungsten-bearing skarn deposits.
Although the Ruby Mountains are not highly mineralized, the range is home to several small mining districts that have yielded gold, silver, and various base metals. In addition, the Ruby Mountains are quite extensive and extremely rugged. Certainly a small gold-bearing vein could have been overlooked in all this vast wilderness. Especially one that was deliberately concealed.
Prospectors may want to concentrate on the contact between the Tertiary granitic rocks and the surrounding limestones. There are numerous small granitic pods south of the main intrusion along the west flank of the Ruby Mountains. These should also be investigated.
The upthrust wedge of Devonian-Mississippian carbonate and siliceous clastic rocks is separated from the older lower Paleozoic limestones by a thrust fault. This fault zone would also be likely prospecting ground. Further south, the area above the old Joy mining camp would be worth a look.
Prospectors must realize that the area of interest for "Swede" Pete's lost lode is quite extensive. The dedicated gold-seeker has about 30 miles of mountain flank to cover.