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Primary gold is Reef or Lode gold where the gold is still deposited in its original host rock. There are a few theories on how gold originated but the main consensus is that the majority of gold nuggets originate from Primary gold deposits. Alluvial Gold (Deposited by water movement) and. Eluvial gold (disintegration of rock at the site where ...

The Extractive Metallurgy of Gold Gold Deposits Types: List of 10 Gold Deposit Class #1 Pegmatites are igneous rocks formed in the final stage of magma crystallization Porphyry Dyke Coarse-grained granite Albitite Gold Deposit Class #2 Carbonatite Carbonatite Related Gold Deposit Class #3 Auriferous Gold Skarn Type Deposit Gold Deposit Class #4 ...

The classification of these deposits is suggested in a monograph on gold (Boyle, 1979), revised to include more recent data; it is based essentially on the general morphology and chemical constitution of a deposit-type and on its geological and geochemical setting, particularly the nature of its host rocks.

Mesothermal gold deposits form half way up through the rise of the melt from the deep crust to the surface usually at a depth of less than 10 km but greater than 1 km. temperatures at these depths are generally somewhere between 450 degrees and 250 degrees Celsius. The term mesothermal veins is really a sack term, referring simply to the depth formation.

Schist As a Gem Material Host Rock. Schist is often the host rock for a variety of gemstones that form in metamorphic rocks. Gem-quality garnet, kyanite, tanzanite, emerald, andalusite, sphene, sapphire, ruby, scapolite, iolite, chrysoberyl and many other gem materials are found in schist.

Veins and reefs of gold-bearing quartz can occur in many types of rock, for example around granites, in volcanic rocks or in regions of black slate, but in most cases these host rocks are not the immediate source of the gold. Gold deposits have formed at many different times during Earth's history.

Definition of host rock. A body of rock serving as a host for other rocks or for mineral deposits; e.g., a pluton containing xenoliths, or any rock in which ore deposits occur. It is a somewhat more specific term than country rock. Ref: AGI.

Prospecting for hardrock gold deposits. Prospectors for hardrock, or lode gold deposits, can use many tools. It is done at the simplest level by surface examination of rock outcrops, looking for exposures of mineral veins, hydrothermal alteration, or rock types known to host gold deposits. Field tools may be nothing more than a rock hammer and ...

Figure 4 summarises the mineral paragenesis of the quartz vein containing gold. The sequence comprises initial host rock formation which latter experienced fracturing. This was subsequently followed by introduction of hydrothermal mineralizing fluid composing of quartz, gold, and magnetite.

Massive sulfide deposits containing pyrite/gold which are embedded in white to cream or gray colored shists Price determined by the number of sulphides and/or metallic inclusions on the surface of the host rock; not assayed; this mine is now back in operation again : Pyrite / Gold ore in matrix Mineral # 1821

Lode gold deposits are usually hosted in basalt or in sediments known as turbidite, although when in faults, they may occupy intrusive igneous rocks such as granite. Lode-gold deposits are intimately associated with orogeny and other plate collision events within geologic history.

Gold is most commonly found along the edges of greenstone belts and associated with structural features. Intensely altered and fractured basalt is a common host rock. The gold is though to be mobilized by hydrothermal solutions during regional metamorphism.

Intensely altered and fractured basalt is a common host rock. The gold is though to be mobilized by hydrothermal solutions during regional metamorphism. The solutions probably contain only a few parts-per billion gold but great volumes of solution can precipitate their gold in a small zone with favorable chemical conditions. The deposit itself ...

Gold and silver are obtained from a variety of ores. Most people think of nuggets and such, but the truth is that very little comes from nuggets - nearly all newly mined gold comes from ores mined from the natural hard rocks that contain gold in tiny, even microscopic particles.

Oct 21, 2018· A couple of nice quartz specimens to add to the collection. What does gold look like in rocks_ Gold bearing rock identification. - Duration: 40:24.

type of ore-controlling structure or host of sedimentary rock-hosted gold deposits in P.R. China. These breccia bodies are conformable with stratigraphic units in the host rock. An example of this is the Shuangwang gold deposit (Fan, S.C. and Jin, Q.H., 1994), which is a large Carlin-type gold .

Host rock is, simply, the rock surrounding the ore deposit. Host rocks, as the definition suggests, may be found as a host to any kind of ore deposit, from gold to uranium. Host rock may also be defined as the type of rock where mineralization occurs. Host rocks are significant in identifying the ...

The effort to understand the geology of gold was perhaps man's first serious effort at understanding the earth's rocks and minerals. Gold is actually a relatively scarce element on the crust of the earth, but it occurs in trace quantities spread throughout many different kinds of rocks and in many different geological environments.

Extracting gold from rock . Updated Tuesday 27th February 2007. Information on how to extract gold from rock, one of the scientists' challenges on the BBC/OU series Rough Science 3. This page was published over five years ago. Please be aware that the information provided on this page may be out of date, or otherwise inaccurate due to the ...

Identifying gold bearing ore just by visual inspection can be very difficult, or even impossible, depending on the concentration of the gold within the rock. Many ores that contain gold contain other metallic metals in them also, so there are likely to be a lot of shiny minerals mixed into the rock which may or .

The Geology of Coarse Gold Formation. ... This is the main reason why some rich hard rock gold districts don't have much in the way of associated placers. The most productive gold vein district in Nevada (not including the Carlin type deposits) was Goldfield. This District was discovered about 1903, and produced nearly five million ounces of ...

The host rock weathers away and the geodes are left on the surface, washed into a stream, or stranded in a residual soil. In these situations the geodes are easily found and collected. Some geodes are produced by mining the host rock, but that method is difficult, costly, and often damages the geode.

Elsewhere, gold is won from deposits of this type in Alaska at the Alaska Juneau mine (Mesozoic); Grass Valley and Nevada City auriferous districts, California (Mesozoic); and the Central City district, Colorado (Tertiary). 7. Disseminated and stockwork gold-silver deposits in igneous, volcanic, and sedimentary rocks

Mar 13, 2018· Gold feels heavy, like a lead fishing weight, when you hold a placer nugget in the palm of your hand. However, weight alone is not enough to identify real gold in a rock. As an amateur, you can test a rock for gold in several ways.
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