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Native metals Native metal is a term used to describe metals discovered in their natural, elemental form – either as an alloy, or in pure form. The list of metals which can occur in native deposits is long, though very few can ...Read more
Native metals
Native metal is a term used to describe metals discovered in their natural, elemental form – either as an alloy, or in pure form.
The list of metals which can occur in native deposits is long, though very few can withstand the natural processes of weathering and oxidization.
Most native metals (including aluminum, arsenic, bismuth, cadmium, chromium, cobalt, iron, lead, mercury, nickel, selenium, tin, titanium, tungsten, and zinc) are highly reactive when exposed to water, light, and other elements of nature – which means they are more likely to occur as small, isolated pockets of reduced ore, or as small flakes or inclusions.
Gold, silver, copper, and platinum are the least reactive of native metals.
This greater capacity for endurance means they are the most likely native metals to be discovered in larger deposits – and their wider availability and occurrence offers a variety of interest to collectors.
Read lessMinerals containing elements of economic value are generally present in all igneous rocks, but the elements may not be concentrated enough to make mining economical. Only in relatively rare circumstances are they in sufficient abundance so that mining is profitable. If the ...Read more
Minerals containing elements of economic value are generally present in all igneous rocks, but the elements may not be concentrated enough to make mining economical.
Only in relatively rare circumstances are they in sufficient abundance so that mining is profitable.
If the minerals are scattered throughout a host rock, but in sufficient amounts to mine profitably, we call the deposit a disseminated deposit.
Disseminated deposits produce most of the world’s diamonds, copper, and molybdenum and also large percentages of the available tin, silver, and mercury.
Often, disseminated ores consist of minerals scattered randomly in a host rock.
Sometimes geological processes concentrate ore minerals in vein deposits consisting of veins that are centimeters to meters thick.
If ore is distributed in many small veins, geologists call the deposit a lode deposit. Vein deposits account for most of the world’s gold and silver mines, and also some copper and lead-zinc mines.
In still other kinds of igneous deposits, ore minerals become concentrated in layer
Read lessMost geologists involved in almost every phase of field geology use geologic maps. For example, petrologists use these maps to determine the location of possible economic resources, such as metal ores, water, or oil. Ceomor· phologists use such maps to ...Read more
Most geologists involved in almost every phase of field geology use geologic maps. For example, petrologists use these maps to determine the location of possible economic resources, such as metal ores, water, or oil. Ceomor· phologists use such maps to detect potential hazards in various areas, such as areas prone to earthquakes, flooding, or landslides. Occasionally, geologic profiles are also provided on these maps to help scientists understand, for example, the rock underlying an area.
Read lessA geologic map is actually a form of topographic map, but in this case it shows the type of sediment or rock outcrops exposed at the Earth’s surface, along with the contour lines. The information on these maps can range ...Read more
A geologic map is actually a form of topographic map, but in this case it shows the type of sediment or rock outcrops exposed at the Earth’s surface, along with the contour lines. The information on these maps can range from the rock type and age to the orientation of rock layers and major (and sometimes minor) geologic features.
Read lessJade and serpentine are two important types of minerals that have applications in jewelry and ornamental industries. The key difference between jade and serpentine is that jade is comparatively harder and less scratchy, whereas serpentine is softer and scratches more ...Read more
Jade and serpentine are two important types of minerals that have applications in jewelry and ornamental industries. The key difference between jade and serpentine is that jade is comparatively harder and less scratchy, whereas serpentine is softer and scratches more easily than jade. Jade is considered to be more precious and valuable than serpentine.
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How are basalt and granite formed
How are basalt and granite formed
Read lessOne major difference between basaltic and granitic magma is their specific mineral contents. Basaltic magma contains between 45 and 55 percent silicon dioxide and is high in magnesium, iron and calcium, while granitic magma contains between 65 and 75 percent ...Read more
One major difference between basaltic and granitic magma is their specific mineral contents. Basaltic magma contains between 45 and 55 percent silicon dioxide and is high in magnesium, iron and calcium, while granitic magma contains between 65 and 75 percent silicon dioxide and only small amounts of those minerals.
Read lessThese three igneous rocks pretty much have the same chemistry and mineralogy. The are all black or very dark grey. The main difference between them is the grain size. Basalt is fine grained and Gabbro is course grained. This is ...Read more
These three igneous rocks pretty much have the same chemistry and mineralogy. The are all black or very dark grey. The main difference between them is the grain size. Basalt is fine grained and Gabbro is course grained. This is due to the rate of cooling of the molten magma. Basalt is a volcanic rock that cooled rapidly when erupted from a volcano, so the crystals did not have much time to grow. . Dolerite was intruded into existing rocks as sills and dykes so it was more insulated than basalt and developed larger crystals. Gabbro cooled very slowly in the magma chamber so the crystals had plenty of time to grow.
If you look at basalt closely you will not normally be able to see the crystals with the naked eye, but you might be able to with a hand lens. This tough rock can be seen being used as cobble stones in to streets of Hull’s Old Town and sometimes in the Avenues and Dukeries. It is also used in cemeteries for memorials and takes a high glossy polish; this makes it hard to photograph because you can see the reflection of the camera and photographer! On modern memorials the lettering is often picked out in white or gold; pictures can be etched in using a laser.
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