Download Gold is called a "noble" metal (an alchemistic term) because it does

“All
that glisters is not gold; Often have you heard that told”
Shakespeare MERCHANT OF
Although gold mines are spread over much of Oregon, almost all of the gold produced
has come from two principal areas: the Klamath Mountains in southwest Oregon,
including Coos, Curry, Douglas, Jackson and Josephine counties; and the Blue Mountains
in northeast Oregon, mostly in Baker and Grant counties.
Prospectors from Illinois discovered placer gold in the Klamath Mountains of southwest
Oregon in 1850, starting a rush to the area. Lode gold deposits were also discovered.
Travellers along the Oregon Trail bound for the Willamette Valley are said to have
discovered gold in northeastern Oregon in 1845, but no production resulted. Mining in
earnest did not begin until 1861.[26]
http://en.wikipedia.org/wiki/Gold_mining_in_the_United_States
Fred C. Dobbs: This is the country where the nuggets of gold are just crying out for you
to take them out of the ground and make 'em shine in coins on the fingers and necks of
swell dames.

Gold is found in three main environments on earth.
1) Within ancient Precambrian shield terranes such as Canada, Brazil, Western
Australia, Zimbabwe and Ghana. These usually occur within 'shear zones' - that is
wide zones of faulting up which superheated fluids were able to rise. These fluids
were unstable and as soon as the temperatures and pressures of these fluids were
normalised, the gold, quartz, pyrite and other minerals were rapidly deposited
within the shear zones.
2) Shear zones and quartz veining have also formed close to modern destructive
plate margins. These plate margins are typical, though not entirely confined to the
'Pacific Rim of Fire' which runs from Chile to Mexico to Alaska to the Philipines
to Indonesia to New Zealand. Here, the effect of the rising heat sources as a result
of igneous activity causes convectional cells to circulate through the rocks
leaching them of trace amounts of gold and other metals. Sub-vertical veins then
break through along shear zones and the minerals are released in a similar way to
that of 1)

3) Because gold is heavy, mineral deposits of the type mentioned above are
eroded / weathered out of their rocks and are carried down the nearby rivers. The
gold resists this movement and lags behind in the headwaters of the streams
whilst other minerals are washed down the stream with relative ease. By this
means the great palaeo-placer gold deposits of the Witwatersrand in South Africa
was formed as have the modern day alluvial gold deposits of the Klondyke in
Canada and those of the South Island of New Zealand
Source(s):
Professional Geologist who has spent much of his working life exploring for gold
deposits.
As most of you already know, gold typically occurs in fractured "host"
rocks (granite, schist, quartz, etc.) as veins or lodes. The Sierra Nevada
Batholith (the source of the California Motherlode Region's gold) is a
good example of this sort of deposit on a grand scale.
Most lodes are formed when super-heated fluids composed of various
chemical constituents circulate through mineralized zones containing
gold (Au), chemically bond with it, and then transport it to new locations
in the earth's crust. The physical differences of various types of rock as
well as the chemical composition of the fluids driven into and around
them account for the vast array of various types of lode gold deposits,
some of which are outlined below:
1) "Smoker" Au Deposits: These deposits occur wherever
superheated waters spring up from vents ("smokers") in the ocean floor
which are typically created by tectonic activity along the earth's crust.
When this happens, metal-rich minerals including small amounts of gold
are deposited in the zone where the superheated, auriferous water is
mixed with the cold seawater it makes contact with.
2) High-Sulphur Hydrothermal Au Deposits: Hydrothermal gold
deposits usually form when gold-laden water is superheated by magma
(molten rock) in the shallowest layers of the earth's crust along lines of
past volcanic activity. The chemical fluids in these sorts of deposits are
sulphur rich, something that caused many an old timer to call these
types of gold ores "sulpherets." (The gold deposits found near
Summitville, CO are a good examples of high-sulphur hydrothermals.)
3) Low-Sulphur Hydrothermal Au Deposits: These deposits are very
similar to the previous deposit type, with gold forming under similar
conditions in similar regions. The main difference is, of course, that the
mineralized chemical fluids involved are low in sulphur. (Gold ores
found near Round Mountain, NV are low-sulphur hydrothermals.)
4) Microscopic or "Invisible" Au Deposits: Formed when specific
chemical interactions take place between super-heated fluids and
sedimentary rock, "invisible" deposits derive their name from the micronsized gold particles that typify them. But don't let the terms microscopic
or invisible fool you. These types of deposits can be very "rich" in terms
of gold values (but require massive operations to mine). (The Carlin and
Meikle Mines in Nevada are good examples.)
5) Uplift or Batholith Au Deposits: Typified by the extensive gold
deposits of California's Motherlode Region, batholiths form when
extensive fracturing of the earth's crust occurs and tremendous uplift
takes place as mountain ranges rise (i.e. the Sierra Nevada Mountains).
As this uplift takes place, mineralized hydrothermal fluids flow into rock
fractures and cracks, usually of a quartzitic nature (these superheated
fluids are created by extremely hot metamorphic rocks buried deep
beneath the earth's surface).
6) Greenstone Belt Au Deposits: These are very ancient gold deposits
geologically speaking (older than 2 billion years), and no longer form on
the earth today. However, examples of these ancient deposits can be
found in Australia, Canada, and Africa in various locations.
7) Placer Au Deposits: Over the course of millenia, fine gold, flakes,
and nuggets are worn away from their source lodes by heat, cold,
pressure, and erosion and begin "migrating" into low-lying areas such
as benches, streambeds, gulches, washes, and the ocean floor. These
easily worked deposits are called "placers" and they are the bread and
butter of most recreational or small-scale miners.
http://goldbedrockgold.blogspot.com/2008/07/bedrock-dreams-geology-101-howgold.html
Exactly how is gold formed? No one knows for sure. The story around this rare metal is truly
an enigma. No one knows how it was formed and who first discovered it. For thousands of
years, gold has been one of the world's most precious commodities. Valued by every major
civilization of record, gold still remains as powerful now as it did in ancient times, perhaps
because of the mystery involving its origins. The following hypotheses suggest how gold
came to be:
The Greek Theory: Gold was probably first spotted in a stream, and Greek philosophers
believed gold was a combination of water and sunlight.
The Hot Water Theory: Surprisingly, the most popular of the three hypothesis is a complex
variation on the primitive idea that gold is a combination of water and sunlight. This
hypothesis states that circulating pools of ground water were heated by volcanoes and
molten rock, and then pushed into crevices in the earth's surface. The water went several
miles into the earth's surface. As the heated water contacted the mineral-rich crust, it began
dissolving the metals in the bedrocks. When the water eventually reached a cooler surface, a
unique, gold-like metal formed.
The Magma Theory: The second hypothesis presupposes that the elements that create gold
are present and expelled from volcanic magma as it cools. Because granite rocks are
solidified magma, this hypothesis especially holds true for gold found near or inside this type
of rock.
The Hot Rock Theory: The third hypothesis concerns gold found in volcanic rocks. It states
the rocks were heated at high temperatures and pressurized, which created a chemical
reaction. As the temperatures cooled and pressure decreased, the rock expelled mineral-rich
water. The minerals in this water eventually created gold.
The presence of gold in both water and earth helps explain the various techniques for
gathering this precious metal. For example, prospectors panned for gold in California during
the Gold Rush, and companies and individual miners have been exploring promising gold
deposits for years
http://www.life123.com/career-money/commodities-2/gold/how-is-gold-formed.shtml
Among igneous rocks, i.e. those formed from magma or molten rock, the most important
difference may be between plutonic and volcanic rocks. Plutonic rocks are formed
underground. They involve the "intrusion" or insertion of magma between other rocks,
which then cools below the surface. Volcanic rocks are formed above ground. They
involve the "extrusion" or eruption of magma, which then is called "lava." The lava cools
upon or very close to the surface. Volcanic rocks can also form from "ash", which is
simply pulverized rock blown into the air (not like the "ash" that results from burning
wood) -- larger rocks are "bombs." Plutonic rocks are named after Pluto, the Greek god of
the underworld, although the word literally means "wealth," probably because precious
metals are generally dug out of the ground. Indeed, gold and silver are characteristically
found in "veins," which are intrusions and so part of plutonic rocks
Occurrence: Widespread in very small quantities in rocks of many kinds throughout the world,
and in sea water. In veins of epithermal origin, typically in quartz with pyrite and other sulfides,
and with tellurides; in pegmatites; in contact metamorphic deposits. Common in placers.
Association: Pyrite, chalcopyrite, arsenopyrite, pyrrhotite, sylvanite, krennerite, calaverite,
altaite, tetradymite, scheelite, ankerite, tourmaline, quartz.
A native element and precious metal, Gold has long been prized for its beauty, resistance to
chemical attack and workability. As it is found as a native element, has a relatively low melting
point (1063 degrees Celsius) and is malleable, it has been used by mankind for thousands of
years.
Gold is used as a standard for international currency and is also widely used in jewelry,
electronics (where its superb properties as a conductor help offset its tremendous cost), dentistry
and in photographic processes.
Gold occurs in significant amounts in three main types of deposits: veins of hydrothermal and
related origin; in consolidated placer deposits, and in unconsolidated placer deposits. It may also
occur in granitic pegmatites, in contact metamorphic deposits, and in hypo-thermal deposits. It is
commonly found as disseminated grains in Quartz veins with Pyrite and other sulphides, or as
rounded grains, flakes or nuggets in placer deposits and in streams and rivers. Gold is often
panned from such deposits by taking advantage of its high density to wash away the lighter
sediments from a pan or sluice.
Nuggets are (almost) exclusively hypogene in origin (Hough et al., 2007).
from
http://www.mindat.org/min-1720.html
Gold is described and known as a precious metal. The combination of gold’s relative
scarcity and its obvious beauty has made it a very valuable commodity throughout the
history of humanity. It is most probably the oldest precious metal known to man. Wars
have been fought over it and countless numbers have died trying to gain it or protect it.
Scientifically speaking, gold is an element, a metal, with an atomic number 79. Its
physical and chemical properties make it ideal for a number of applications. It is very
stable and as a result seldom combines with other elements. In other words, it does not
corrode or rust. It conducts electricity very well (only silver and copper are better
conductors of electricity). It conducts heat very well. Gold is very malleable which means
it can be hammered into shapes. Gold is so malleable that it can be hammered into a sheet
so thin that light can pass through it. It is also ductile, which means it can be drawn into
long, thin wires: a wire thread approximately 50 miles long can be drawn from a single
troy ounce of gold (31.1 grams). It is also one of the densest metals: a cubic foot of gold
weighs over 1,200 pounds.
Name
Gold’s chemical symbol is Au. It comes from the Latin word aurum which means shining
dawn, a reference to its bright yellow color and shiny luster. The English word gold has
its origins in Middle English.
Sources
Gold is found in two major types of deposits. Lode deposits are deposits where gold is
found in cracks and veins in rocks. These are also called vein deposits. The second type
of gold deposit is called a placer deposit. Placer deposits are formed by moving water
that has eroded gold out of lode deposits. When the speed of the water in a river slows
sufficiently, the heavy gold falls to the bottom and accumulates in the sand of the
riverbed. A third major source of gold is as a by-product of copper and silver mining.
Gold is so valuable that it is worth the effort to recover even minute amounts from copper
and silver ore.
It is estimated that the total amount of gold yet to be retrieved from the Earth is 100,000
tons. South Africa is the world’s largest producer of gold and is estimated to have half of
these gold resources. The United States and Brazil each have significant amounts of the
world’s gold resources. Approximately one-fifth of the total resources of gold in the
world is by-product from copper and silver ores.
In the United States, Alaska and Nevada are the main producers of gold. Nevada
produces the majority of the gold produced in all of the United States. The remaining are
from placer deposits in Alaska, and other gold deposits in western states. Most of the
gold recovered in the United States is recovered by only about 30 mines. The largest gold
mines in the United States today are located in northern Nevada.
From
http://www.mii.org/Minerals/photogold.php
Gold is formed in the supernova explosions of stars. At that time, it is just gold gas.
When it cools down, the gas becomes dust. As all the dust from the supernova cools
down and starts to stick together, it forms planets. But the planets are very hot and molten
at first. So the gold is molten also.
The various minerals in the molten planet tend to float to various levels, each mineral to
its own level. This is just a tendency, not an absolute, because the molten material does a
lot of mixing around. But some of the gold collects into pockets and veins. Because of the
way gold is, it doesn't form compounds with other stuff very well. So it segregates out by
itself, and forms nuggets.
From an answer page
Gold in its natural mineral form almost always has traces of silver, and may also contain traces of
copper and iron. A Gold nugget is usually 70 to 95 percent gold, and the remainder mostly silver.
The color of pure Gold is bright golden yellow, but the greater the silver content, the whiter its
color is. Much of the gold mined is actually from gold ore rather then actual Gold specimens. The
ore is often brown, iron-stained rock or massive white Quartz, and usually contains only minute
traces of gold. To extract the gold, the ore is crushed, then the gold is separated from the ore by
various methods.
Gold nuggets, a popular form of Gold with collectors, are formed when erosion causes a large
piece of Gold to separate from its mother rock, and then gets carried into a stream or river. The
flowing water tumbles the Gold, giving it its distinct rounded shape. The Gold eventually settles at
the bottom of the water, and due to its heaviness remains there. Other nuggets also get caught in
the same area, forming a placer deposit.
Gold is one of the heaviest minerals. When pure, it has a specific gravity (SG) of 19.3. Due to its
weight, it can be panned because the Gold sinks to the bottom. In addition, it can be easily
separated from other substances due to the weight differences. Gold is also the most malleable
and ductile substance known. It can be flattened out to less than .00001 of an inch (less than
.000065 cm), and a 1 oz. (28 gram) mass can stretch out to a distance of over 50 miles (75
kilometers). Gold is also one of the most resistant metals. It won't tarnish, discolor, crumble, or be
affected by most solvents. This adds on to the uniqueness and allure of this mineral.
Gold is usually associated with Pyrite and other sulfides, and sometimes may not be noticed
because of the association with these resembling minerals.
From http://www.minerals.net/mineral/elements/gold/gold.htm
Gold is an element, so it was formed at the beginning of the universe, just like all other
elements. Gold reaches the surface of the Earth through cracks in the earths surface
where superheated water contains dissolved gold. As the water cools down, the gold
forms veins in the rocks.
http://gottatopic.com/how-is-gold-formed/
gold - how it’s made MODERN GEOLOGY CORE SAMPLING
http://www.youtube.com/watch?v=MyOKNR1JCs0
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Gold is called a "noble" metal (an alchemistic term) because it does not oxidize under
ordinary conditions. Its chemical symbol Au is derived from the Latin word "aurum." In
pure form gold has a metallic luster and is sun yellow, but mixtures of other metals, such
as silver, copper, nickel, platinum, palladium, tellurium, and iron, with gold create
various color hues ranging from silver-white to green and orange-red.
Pure gold is relatively soft--it has about the hardness of a penny. It is the most malleable
and ductile of metals. The specific gravity or density of pure gold is 19.3 compared to
14.0 for mercury and 11.4 for lead.
Impure gold, as it commonly occurs in deposits, has a density of 16 to 18, whereas the
associated waste rock (gangue) has a density of about 2.5. The difference in density
enables gold to be concentrated by gravity and permits the separation of gold from clay,
silt, sand, and gravel by various agitating and collecting devices such as the gold pan,
rocker, and sluicebox.
Gold is relatively scarce in the earth, but it occurs in many different kinds of rocks and in
many different geological environments. Though scarce, gold is concentrated by geologic
processes to form commercial deposits of two principal types: lode (primary) deposits
and placer (secondary) deposits.
Lode deposits are the targets for the "hardrock" prospector seeking gold at the site of its
deposition from mineralizing solutions. Geologists have proposed various hypotheses to
explain the source of solutions from which mineral constituents are precipitated in lode
deposits.
One widely accepted hypothesis proposes that many gold deposits, especially those found
in volcanic and sedimentary rocks, formed from circulating ground waters driven by heat
from bodies of magma (molten rock) intruded into the Earth's crust within about 2 to 5
miles of the surface. Active geothermal systems, which are exploited in parts of the
United States for natural hot water and steam, provide a modern analog for these golddepositing systems. Most of the water in geothermal systems originates as rainfall, which
moves downward through fractures and permeable beds in cooler parts of the crust and is
drawn laterally into areas heated by magma, where it is driven upward through fractures.
As the water is heated, it dissolves metals from the surrounding rocks. When the heated
waters reach cooler rocks at shallower depths, metallic minerals precipitate to form veins
or blanket-like ore bodies.
Another hypothesis suggests that gold-bearing solutions may be expelled from magma as
it cools, precipitating ore materials as they move into cooler surrounding rocks. This
hypothesis is applied particularly to gold deposits located in or near masses of granitic
rock, which represent solidified magma.
A third hypothesis is applied mainly to gold-bearing veins in metamorphic rocks that
occur in mountain belts at continental margins. In the mountain-building process,
sedimentary and volcanic rocks may be deeply buried or thrust under the edge of the
continent, where they are subjected to high temperatures and pressures resulting in
chemical reactions that change the rocks to new mineral assemblages (metamorphism).
This hypothesis suggests that water is expelled from the rocks and migrates upwards,
precipitating ore materials as pressures and temperatures decrease. The ore metals are
thought to originate from the rocks undergoing active metamorphism.
Placer deposits represent concentrations of gold derived from lode deposits by erosion,
disintegration or decomposition of the enclosing rock, and subsequent concentration by
gravity.
Gold is extremely resistant to weathering and, when freed from enclosing rocks, is
carried downstream as metallic particles consisting of "dust," flakes, grains, or nuggets.
Gold particles in stream deposits are often concentrated on or near bedrock, because they
move downward during high-water periods when the entire bed load of sand, gravel, and
boulders is agitated and is moving downstream. Fine gold particles collect in depressions
or in pockets in sand and gravel bars where the stream current slackens. Concentrations
of gold in gravel are called "pay streaks."
In gold-bearing country, prospectors look for gold where coarse sands and gravel have
accumulated and where "black sands" have concentrated and settled with the gold.
Magnetite is the most common mineral in black sands, but other heavy minerals such as
cassiterite, monazite, ilmenite, chromite, platinum-group metals, and some gem stones
may be present.
Placer deposits have formed in the same manner throughout the Earth's history. The
processes of weathering and erosion create surface placer deposits that may be buried
under rock debris. Although these "fossil" placers are subsequently cemented into hard
rocks, the shape and characteriAbout 15 percent of the gold produced in the United States
has come from mining other metallic ores. Where base metals- -such as copper, lead, and
zinc--are deposited, either in veins or as scattered mineral grains, minor amounts of gold
are commonly deposited with them. Deposits of this type are mined for the predominant
metals, but the gold is also recovered as a byproduct during processing of the ore. Most
byproduct gold has come from porphyry deposits, which are so large that even though
they contain only a small amount of gold per ton of ore, so much rock is mined that a
substantial amount of gold is recovered. stics of old river channels are still recognizable.
Goldby Harold Kirkemo, William L.
Newman, and Roger P. AshleyFrom:
http://pubs.usgs.gov/gip/prospect1/goldgip.html
goldbarsandcash
Applegateriverbedrock
Galicecreekgoldsign
Jacksoncounty1914
Jacksoncreek
Josephinecounty1895
Waldooregon1890
All above from:
http://www.oregongold.net/category/oregon-gold/southern-oregon-gold-oregon-gold/
middleforkjohndaybluebucket
goldpanner
http://www.oregongold.net/category/oregon-gold/northeastern-oregon-gold/
riverplacergold
residualhillgold
from
http://nevada-outback-gems.com/prospect/gold_specimen/Natural_gold.htm
arrastras
from
http://www.historycooperative.org/journals/sia/30.2/vanbueren.html
bucketdredgebaker1941
from
http://www.historycooperative.org/journals/ohq/109.1/dielman.html
goldinpan
http://gottatopic.com/how-is-gold-formed/
oregoncounties
from
http://www.oregongold.net/oregon-maps/
geopl350
http://www.oregongeology.org/sub/learnmore/learnmore.htm