JewelryCycle.com - Open source, educational jewelry.

Treasure Hunting in Nevada County

Treasure Hunting in Nevada County

Map from: https://www.davidrumsey.com

Along with breathtaking beauty, and colorful artist culture. Nevada County offers a rich history of treasure. More gold than we will ever know was pulled out of the ground here. Unfortunately, it came with the complete disregard of an indigenous population. Survived by the Nisenan Rancheria people. Extreme prejudice to other races. Chinese, Latin Americans, etc.. Poisoning the water with heavy metals. Not only mercury, but many others including cadmium, lead, zinc, copper, arsenic, selenium, etc.. They are now finding these metals in the food we eat. As well as the destruction of many acres of wilderness. Hydraulic mining, ranching, lumber, etc.. Read more about some of this from a contemporary blogger: Hank Meals http://yubatreadhead.blogspot.com/

The modern treasure hunter can learn from this, and approach treasure hunting as an adventure. Where the importance is placed on the journey, and a looser definition is used for treasure. Where care is taken to preserve our natural heritage. At the same time, there is nothing like finding something shiny at the end of the hunt. Because of this, I will be talking about a number of different methods for finding gold, and related treasures in Nevada County. I will also attempt to provide resources so you can be conscientious about conservation of la tierra.

Gold is the most famous of minerals found in this area. The abundance of gold here this close to the surface is extremely rare. One of the few places in the world you can count on finding “color” everytime you go panning. However, I’m told you can find other minerals. For example:
http://www.goldmaps.com/ancient_tertiary_rivers_of_gold.htm 

Platinum
Platinum is widely distributed in the gravels of the Tertiary rivers of the Sierra Nevada. The platinum is always associated with the gold. Some of the counties where platinum has been proven to be present in the sands are: Butte, Calaveras, Nevada, Placer, Plumas, Sacramento and Yuba.

Garnet
Garnet is widely distributed especially in the vicinity of granitic contacts. It is usually found in small rounded grains of red to purplish color. The largest quantity recorded was from the black sands at Rough and Ready, Nevada County at 446 pounds to the ton.

Zircon
Zircon is universally present. In some local areas it has been found in considerable quantities, such as at Placerville and at the North Fork of the American River in Placer County. The greatest relative quantity was found in black sand from a channel at Nevada City. It yielded 928 pounds to the ton.

Copper
Small flakes of metallic copper are occasionally observed.

Pyrite
Pyrite is of common occurrence in the gravels.

Diamonds
Diamonds have been found to occur with the gold, mainly at Cherokee Flat in Butte County and in the gravels at Placerville, El Dorado County. The diamonds that have been found were generally of small size and yellowish color. As is the case of diamonds in North Carolina and South Carolina, the diamonds in the California Mother Lode region are mostly scattered. Diamonds come up through the rock through a “pipe” of relatively small diameter, such as the diamond pipes in South Africa. (The state of Arkansas has acquired a diamond property at Murfreesboro where the public is permitted to search for diamonds. The diamonds are of good size and high quality. The Arkansas property is Crater of Diamonds State Park.)

As well as quartz, feldspar, serpentine, amethyst, agate, chalcedony, jasper, limestone, marble, and granite of many colors. More on the other minerals in future posts. But first,

Gold
https://en.wikipedia.org/wiki/Gold

Alchemists symbol for gold was the circle with a point at its center (☉), which was also the astrological symbol and the ancient Chinese character for the Sun; a symbol shared by many other cultures around the globe.

Gold is thought to have been produced in supernova nucleosynthesis, from the collisionof neutron stars,[5] and to have been present in the dust from which the Solar System formed. Because the Earth was molten when it was formed, almost all of the gold present in the early Earth probably sank into the planetary core. Therefore, most of the gold that is in the Earth’s crust and mantle is thought to have been delivered to Earth later, by asteroid impacts during the Late Heavy Bombardment, about 4 billion years ago.[6][7]

Gold often occurs in free elemental (native) form, as nuggets or grains, in rocks, in veins, and in alluvial deposits. Native gold occurs as very small to microscopic particles embedded in rock, often together with quartz or sulfide minerals such as “Fool’s Gold”, which is a pyrite.[59]These are called lode deposits. The metal in a native state is also found in the form of free flakes, grains or larger nuggets[58] that have been eroded from rocks and end up in alluvial deposits called placer deposits. Such free gold is always richer at the surface of gold-bearing veins[clarification needed] owing to the oxidation of accompanying minerals followed by weathering, and washing of the dust into streams and rivers, where it collects and can be welded by water action to form nuggets.

Occurrences of Gold
Paragenetic Mode(s):

Gold Deposits in the Sierra Nevada Foothills
The gold region is practically confined to the first belt, along the west slopes of the Sierra Nevada, intersected by nearly parallel rivers, and broken by deep canons. An intrusive core of granite forms the central feature, which becomes gradually more exposed and extensive, till, in latitude 36-7°, it reaches almost from crest to plain. The core is flanked by metamorphic slates of Triassic and Jurassic age, much tilted, often vertical, the strike being generally parallel with the axis of the range, and in the south dipping toward the east. This so-called auriferous slate formation consists of metamorphic, crystalline, argilaceous, chloritic, and talcose slates. In the extreme north-west it appears with though subordinate to granite. Gradually it gains in importance as the superimposed lava in Butte and Plumas counties decreases, and north of the American River it expands over nearly the entire slope; but after this it again contracts, especially south of Mariposa; beyond the junction of the ranges it reappears in connection with granite. To the same formation are confined the payable veins of gold quartz, chiefly in the vicinity of crystalline and eruptive rocks. They vary in thickness from a line to two score feet or more, and follow a course which usually coincides with that of the mountain chain, that is, north-northwest with a steep dip eastward. The most remarkable vein is the extensive mother lode of the Sierra Nevada, which has been traced for over 60 miles from the Cosumnes to Mariposa.
The slate formation is covered by cretaceous, tertiary, and post-tertiary deposits, of which the marine sedimentary, chiefly soft sandstone, made up of granite debris, occurs all along the foothills, conspicuously in Kern county. The lava region extends through Plumas and Butte northward round the volcanic cones headed by mounts Lassen and Shasta, whose overflows have hidden the gold formation of so large an area. The wide-spread deposits of gravel are attributed to a system of tertiary rivers long since filled up and dead, which ran in nearly the same direction as the present streams, and with greater slope and wider channels. Eroding the auriferous slates and their quartz veins, these river currents spread the detritus in deposits varying from fine clay and sand to rolled pebbles, and boulders weighing several tons, and extending from perhaps 300 or 400 feet in width at the bottom to several thousand feet at the top, and from a depth of a few inches to 600 or 700 feet. The whole mass is permeated with gold, the larger lumps remaining near their source, while the finer particles were carried along for miles. The most remarkable of these gravel currents is the Dead Blue River, so called from the bluish color of the sand mixed with the pebbles and boulders, which runs parallel to the Sacramento some fifty miles eastward, with an average width of a quarter of a mile. The depth of detritus averages three hundred feet, and is very rich in the lower parts, where the debris is coarser and full of quartz. Although the so-called pay dirt, or remunerative stratum, lies in alluvial deposits nearly always within ten feet of the bedrock, and frequently permeates this for a foot or so in the slate formations, yet the top layers often contain gold in payable quantities, even in the upper portions of high banks, which can be washed by the cheap hydraulic process.

More reading here: Gold-Bearing Gravel of the Ancestral Yuba River, Sierra Nevada, California GEOLOGICAL SURVEY PROFESSIONAL PAPER 772 https://pubs.usgs.gov/pp/0772/report.pdf


Finding Gold:

  • Placer mining in the contemporary rivers, creeks, and ravines. Using pan and sluice box. Look for perpendicular cracks and riffles in bedrock, gravels, and black sand. Pay attention to quartz that might contain gold. Look for pyrite, or colored mineralization: black, grey, green, brown, red. From metals like copper, iron, etc..
  • Placer nugget sniping by eye or with a metal detector. Search in likely spots along contemporary or ancient river beds. Look in cracks and crevices. Research local geology, and the path of the Tertiary Pliocene Yuba channel. Detect around old mine tailings, mines, and miner camps.
  • Placer mining ancient tertiary pliocene river gravel beds. Either dry or where a contemporary waterway intersects the ancient channel. Auriferous gravels. Black sand. Blue gravel. Blue cement. Search for red oxidized layer above.
  • Lode quartz mining. Tailings. Existing mines. Quartz ore sulfides. Look for Quartz with gold, pyrite, or mineralization black, grey, brown, red. Ore will need to be crushed, and then refined.
  • Historical research and treasure hunting for the old mining camp sites and older artifacts. With a metal detector, after a heavy rain, or recent construction. Bottles, Coins, etc… Please respect property rights, and any historical or archaeological ordinances. Draw a detailed map of any find of historical significance. Remember when digging any holes, be sure to fill them in. Leave no trace.
  • Electronics scrapping. 10% of gold in the world is used for industry. Be careful with chemicals. More on this in a later post.

    More reading: http://www.goldgold.com/gold-prospectingplacer-geology.html

Accessories

  • Water, hat, and handkerchief. Stay hydrated!
  • Gold pans, screens and buckets.
  • Strong Magnet to quickly pickup iron trash and ‘hot rocks’ before digging
  • Pick to hammer through rocky ground
  • Trowel or fork
  • Plastic Vials to store your fine gold
  • Metal detector
    • How to choose a metal detector: : https://www.smarterhobby.com/metal-detecting/best-metal-detector-gold/
    • Plastic scoop to wave dirt/rocks over coil during recovery
    • Pinpointer or coil probe to quickly pinpoint those small nuggets
    • Coil Cover to protect your coil from damage
    • Shoulder or chest harness to take the weight of the detector off your arm
    • Different coils to adapt to the location your hunting
    • Headphones to hear those faint gold signals
Check out this link on how to stake a claim on public BLM land:

Online Maps & Tools

Local Sites:

  • Mines:
    • Empire mine
    • Northstar Museum
    • 16in1 mine
  • Museums:
    • Firehouse #1 Museum
    • Miner’s Foundry
  • Merchants:
    • The rock shop
    • Crystal Empire Gems

Local Research

Literature:

Angle of Repose

A 1971 novel by Wallace Stegner about a wheelchair-using historian, Lyman Ward, who has lost connection with his son and living family and decides to write about his frontier-era grandparents. It won the Pulitzer Prize for Fiction in 1972. The novel is directly based on the letters of Mary Hallock Foote, later published as A Victorian Gentlewoman in the Far West.

Explanation of the novel’s title

ean·gle of re·pose (noun)
the steepest angle at which a sloping surface formed of a particular loose material is stable.

The title is an engineering term for the angle at which soil finally settles after, for example, being dumped from a mine as tailings. It seems to describe the loose wandering of the Ward family as they try to carve out a civilized existence in the West and, Susan hopes, to return to the East as successes. The story details Oliver’s struggles on various mining, hydrology and construction engineering jobs, and Susan’s adaptation to a hard life.
Another view has to do with a typical construction of canals and the drowning of Ward’s daughter in a canal. Canal banks are sometimes simply piled mounds of dirt. Slanted walls of dirt are left at the angle of repose after the canal is built. Small disturbances to the dirt can cause it to slide down. Ward’s daughter fell into a canal and couldn’t climb out because of this.

https://en.wikipedia.org/wiki/Angle_of_Repose

bigaumap

Liked it? Take a second to support J P on Patreon!