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What is difference between Gold and Pyrite?
The difference between gold and pyrite: 🔥 ● Gold - Crystals form as cubes or octahedrons but are rare. The usual habits are grains, flakes, nuggets and dendritic masses. Bright yellow color is tarnish resistant. Gold is often rich in silver, when it is paler in color. The band is golden yellow. GoldRead more
The difference between gold and pyrite: 🔥
See less● Gold – Crystals form as cubes or octahedrons but are rare. The usual habits are grains, flakes, nuggets and dendritic masses. Bright yellow color is tarnish resistant. Gold is often rich in silver, when it is paler in color. The band is golden yellow. Gold is opaque and its luster is metallic.
Formation:
Forms mainly in hydrothermal veins, often associated with quartz and sulphides. It also occurs in placer deposits of unconsolidated sand and in sandstone and conglomerate. It is possible to find alluvial gold in the form of grains or nuggets in stream beds. Gold panning by sieving sediments is an age-old method of searching for this rare and precious mineral. Gold can be confused with pyrite and chalcopyrite at first, but only a few tests are needed to identify it.
TESTS Insoluble in all simple acids; soluble in aqua regia.
Group: NATIVE ELEMENTS
Composition: Gold
Hardness: 2½–3
GS: 7:30 p.m.
Cleavage: None
● Pyrite – This mineral occurs as cubic, pyritohedral or octahedral crystals; pairing is common.
The crystal faces are frequently striated. Pyrite can be massive, granular, reniform, stalactitic, botryoidal and nodular. The pale yellow color gives rise to its nickname, “fool’s gold”. It has a greenish-black stripe. Pyrite is opaque and has a metallic luster.
Formation:
Pyrite is a common accessory mineral in igneous, sedimentary, and metamorphic rocks.
TESTS Gives off sparks on impact with a hard metal object. Fuses quite easily.
Group: SULPHIDES
Composition: FeS₂
Hardness: 6–6½
OS: 5.00–5.03
Cleavage: Indistinct
Fracture: conchoidal to uneven
What is a placer deposit?
⚒️ Placer deposit ⚒️ 💠 Placer deposit, natural concentration of heavy minerals caused by the effect of gravity on moving particles. 💠 When heavy, stable minerals are freed from their matrix by weathering processes, they are slowly washed downslope into streams that quickly winnow the lighter matrix.Read more
⚒️ Placer deposit ⚒️
💠 Placer deposit, natural concentration of heavy minerals caused by the effect of gravity on moving particles.
💠 When heavy, stable minerals are freed from their matrix by weathering processes, they are slowly washed downslope into streams that quickly winnow the lighter matrix.
💠Thus the heavy minerals become concentrated in stream, beach, and lag (residual) gravels and constitute workable ore deposits.
💠 Minerals that form placer deposits have high specific gravity, are chemically resistant to weathering, and are durable; such minerals include gold, platinum, cassiterite, magnetite, chromite, ilmenite, rutile, native copper, zircon, monazite, and various gemstones.
💠 There are several varieties of placer deposits: stream, or alluvial, placers; eluvial placers; beach placers; and eolian placers.
💠 Stream placers, by far the most important, have yielded the most placer gold, cassiterite, platinum, and gemstones.
💠 Primitive mining probably began with such deposits, and their ease of mining and sometime great richness have made them the cause of some of the world’s greatest gold and diamond “rushes.” Stream placers depend on swiftly flowing water for their concentration.
💠 Because the ability to transport solid material varies approximately as the square of the velocity, the flow rate plays an important part; thus, where the velocity decreases, heavy minerals are deposited much more quickly than the light ones.
💠 Examples of stream placers include the rich gold deposits of Alaska and the Klondike, the platinum placers of the Urals, the tin (cassiterite) deposits of Malaysia, Thailand, and Indonesia, and the diamond placers of Congo (Kinshasa) and Angola.
See lessHow diamomd formation in earth’s mantle?
💎 Diamonds were formed over 3 billion years ago deep within the Earth’s crust under conditions of intense heat and pressure that cause carbon atoms to crystallise forming diamonds. 💎 Diamonds are found at a depth of approx. 150-200km below the surface of the Earth. Here, temperatures averageRead more
💎 Diamonds were formed over 3 billion years ago deep within the Earth’s crust under conditions of intense heat and pressure that cause carbon atoms to crystallise forming diamonds.
💎 Diamonds are found at a depth of approx. 150-200km below the surface of the Earth. Here, temperatures average 900 to 1,300 degrees Celsius and at a pressure of 45 to 60 kilobars (which is around 50,000 times that of atmospheric pressure at the Earth’s surface).
👉 Under these conditions, molten lamproite and kimberlite (commonly known as magma) are also formed within the Earth’s upper mantle and expand at a rapid rate. This expansion causes the magma to erupt, forcing it to the Earth’s surface and taking along with it diamond bearing rocks. Moving at an incredible speed, the magma takes the path with least resistance, forming a ‘pipe’ to the surface.
💎 As it cools the magma hardens to form Kimberlite and settles in vertical structures known as kimberlite pipes. These kimberlite pipes are the most significant source of diamonds, yet it is estimated that only 1 in every 200 kimberlite pipes contain gem-quality diamonds.
👉 The name ‘Kimberlite’ was derived from the South African town of Kimberley where the first diamonds were found in this type of rock.
💎 Coal has rarely – if ever – played a role in the formation of diamonds. In fact, most diamonds that have been dated are much older than Earth’s first land plants – the source material of coal! That alone should be enough evidence to shut down the idea that Earth’s diamond deposits were formed from coal.
See lessWhat is difference between granite and basalt
Differences between basalt and granite Although there are some similarities between basalt and granite, there are also significant differences between these two rock types. Basalt is volcanic, or extrusive, forming at the surface, while granite is plutonic, or intrusive, forming beneath the sRead more
Differences between basalt and granite
Although there are some similarities between basalt and granite, there are also significant differences between these two rock types.
Basalt is volcanic, or extrusive, forming at the surface, while granite is plutonic, or intrusive, forming beneath the surface.
Basalt is mafic while granite is felsic
Basalt is common on both Earth and other Solar System bodies such as the Moon and Mars while granite is only common on Earth and rare elsewhere in the Solar System
Basalt can form in a few days to months, whereas granite plutons can take millions of years to cool and harden.
Basalt is more common in oceanic crust while granite is more common in continental crust.
See lessWhat is the study of geology?
Geology is the study of the earth (geo means earth, and ology means study of). This is a very simple definition for something so complex. Geology involves studying the materials that make up the earth, the features and structures found on Earth as well as the processes that act upon them. Geology alRead more
Geology is the study of the earth (geo means earth, and ology means study of). This is a very simple definition for something so complex. Geology involves studying the materials that make up the earth, the features and structures found on Earth as well as the processes that act upon them. Geology also deals with the study of the history of all life that’s ever lived on or is living on the earth now. Studying how life and our planet have changed over time is an important part of geology.
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