How Gemstones Get Their Specific Colours?

Gemstones give very beautiful colour variety which attracts to the eyes of buyers. If people like the particular gemstones, it is because of their colour. Specific colour is known as gem colour. So, how the gemstones get their specific colour and how they turn into that particular colour? Here are some points discussed under below:-

What Causes Gemstone Color?

There are number of gemstones with great variety of colours. Each has its own colour characteristics. The causes of colours in the gemstones are basically from chemical composition of the gemstones. This should be kept in mind that many minerals have coloureless form in their pure form. Inclusion of impurities in their structure leads to their colours.

The transitional metal group have such kind of elements copper, chromium, iron, gold, nickel and so on. Then, there are some rare earth series having elements such as gadolinium, erbium and yttrium. The spectra not adsorbed by the gems is transmitted or reflected back to the viewer. We see the wave lengths of light and process them as colour. The net result of the wavelengths that pass through the gem, gives the final color to the gemstone. In order to see color, we need at least 3 variables:

  • Light
  • A substance
  • Vision (the eye)

White is consisted on spectral colours which can be seen in rainbow normally. The colours of rainbow are red, yellow, orange, gree, indigo, blue and ciolet. Every colour among these rainbow colours travel at particular wavelength. For example, for red colour, it is 700mm and for violet colour, it is 400 mm. Each carries particular amount of energy.

When a substance catches all the spectral “rainbow” colours except red, the residual colour is red. So the result will be in red colour. Similarly, if substance absorbs all except red and blue, the residual colour ( net result) is purple colour. There are approximately 16 million of combination that can produce colour.  Light energy to heat is transformed by the result of absorption of light. White colour does not absorb light. It is good in use to keep heat away.

It is not necessary to have presence of transitional metal for the origin of the colour in gems. There is other factor of absorption of wavelengths of visible light, the transfer of electrons between ions in gemstone structure.  The absence of an ion in a specific location in the structure, or the presence of a foreign non-transition metal ion, can also lead to colouration, as can simple diffraction of light through the crystal’s structure.

Gems with having impurities which causes colour are called allochromatic. In case of having purity, they will be colourless. There is another condition for causing a colour which is called idiohromatic in which gemstones have such elements which are necessary for chemical structure. There are two type of coloring agents as a chemical structure or impurities.

  • Idiochromatic – minerals get colours by an element included in their chemical composition or chemical formula such as Malachite.
  • Allochromatic – Colours happens due to impurities and not part of their chemical compositions such as Emerald green emerald, pink morganite, and blue to blue-green aquamarine

Some elements’s Role in colour variety:-

Titanium Blue
Vanadium Green / Color change
Chromium Red – Green
Manganese Pink
Iron Red – Green – Yellow
Cobalt Blue
Nickel Green
Copper Green – Blue

List of Gemstones with colour reasons

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Aquamarine is variety of beryl. The iron in the gem caused pale colour.

Emerald green color due to the presence of both iron and titanium.

Garnet deep colour is from iron.

Peridot is usually found in volcanos. This is form of Olivine.  The yellow-green color comes from iron.

Ruby if form of Corundum. The colour is normally due to Chromium. The colour of ruby is pink to red normally

Turquoise, the opaque mineral, gets its colour from Copper

Sapphire is variety of Corundum . In fact corundum in any colour except red is called sapphire. Here is Purple sapphire is from Kashmir, Pakistan. The blue is from Madagascar. The colour in sapphire is from  iron and titanium.

 

Helium – The crisis that was solved before it took hold

Worldwide, our usage of Helium grows year on year. From MRI scanners in medical facilities, nuclear reactors and even party balloons.

Helium is not a resource we can simply create more of – The gas is formed during the natural radioactive decay of Uranium. It has also not been a focus of exploration for many years, despite looming shortages worldwide.

This is due, in part, to the selling of huge Helium reserves by the United States – Estimated to be about 40 percent of the total market supply. The United States began stockpiling the rare gas in the early 1960’s, as a buffer against future shortfalls. However, in 1996 an act passed (“The Helium Privatization Act”) prevented the Government from increasing the stockpile. In response, the United States started selling off this huge stockpile at below market prices, discouraging exploration and development of new deposits. A new bill has since been passed to maintain the reserves going forward.

Enter Helium one and the East African Rift Valley – One of the marvels of geology

To date, Helium has been discovered accidentally, usually while drilling for oil. The Norwegian company, Helium One, has taken a new approach – Their research shows that the heat created in active volcanic zones is enough to release Helium from rocks that carry this precious gas into trap systems, if present.

Of course, the laws of geology still apply, and things get complicated – The gas has to be trapped in such a way as to form an economically viable deposit, and the source area, if related to intense heat produced by volcanism, needs to be far enough away from the heat source so as not to be contaminated by other volcanic gasses. This is defined by the researchers as the “goldilocks zone” – a term often used in astrophysics to define the planetary orbit around a star that has just the right conditions for life to form. The similarity in goals, although with distinctly different outcomes, is easy to see.

In line with their models, the researchers believe that the Helium located in Tanzania is related to high intensity heating and fracturing of both the Mozambique belt (Proterozoic) and the Tanzanian Craton (Archean), by East African Rift System.

They have further found strong movement of Helium from deep to shallow crustal levels along fault structures (Of the East African Rift System), increasing the chance of good Helium trap systems to be developed.

The East African Rift System can be divided into two branches – The Western Rift, also called the Albertine Rift, extends from the Northern end of Lake Albert to the Southern end of Lake Tanganyika, the deepest lake in the world – a startling 1470 metres!

A volcanic system in the East African Rift Valley, as seen in Ethiopia.

The Eastern Rift, also called the Gregory Rift, lies within the Mozambique Belt. It has been shown that the Eastern Rift is caused by the ongoing separation of the Somali and Nubian plates, driven by a rising thermal plume. Much of the energy required to release Helium from source rocks is related to this system.

All these years of research led to one, amazing achievement – Helium One has started to define a resource of about 54 billion cubic feet, in one small portion of the Rift Valley! Exploration continues to this day, with high hopes of expanding the resource to one that will support us for many generations to come.

Most of us don’t realize how close we were to the cessation of vital equipment requiring Helium, across many industries that impact our daily lives.

Information for this article was sourced from –

Sci-news.com

Livescience.com

Forbes.com

Allafrica.com

African and Arabian Tectonic Plates

Wikipedia

Reason for Dinosaurs Extinction they could not Hatch quickly

This has been mysterious that why dinosaurs extinct on Earth after the Asteroid stroke the earth bringing about severe destruction. Paleontologists have observed through a discovery that young dinosaur took so much time to hatch.

Richard Attenborough watches as a dinosaur hatches in Jurassic Park

They could not grow quickly in adulthood that 65 million years ago, their population was fail to recover immediately from the impact of destruction.

Whereas other animals and birds quickly restored their population by quick hatching process in weeks. According to the The Telegraph , this has been discovered by Florida State University and Calgary University. Based on marks on the teeth of embryos and babies, they analyzed to calculate the time in which dinosaurs took time to hatch.

Gregory Erickson is a professor of biological science at Florida State University CREDIT: FSU PHOTOGRAPHY SERVICES

It can be judged from new layers of teeth which grew each day like layers of trees. The layers are visible in microscopic lines of the dentine. It took Dinosaur to hatch two to three months.

“Some of the greatest riddles about dinosaurs pertain to their embryology, virtually nothing is known,” Gregory Erickson, professor of biological science at Florida said.

“We suspect our findings have implications for understanding why dinosaurs went extinct at the end of the Cretaceous period, whereas amphibians, birds, mammals and other reptiles made it through and prospered.”

It has been under observation and assumption that birds belong to dinosaur category. Duration of incubation of dinosaur is similar to birds. The duration hatching was 11 to 85 days which did not support in the growth of dinosaur. Finally it can be said that mystery of dinosaurs extinction after the Cretaceous meteor strike has been solved fully. The animals / mammals developed and grew with passage of time whereas dinosaur could not do this.

The mystery of why the dinosaurs  became extinct after the Cretaceous meteor strike, while birds and mammals flourished, may finally have been solved.

Paleontologists have discovered that dinosaur young took so long to hatch and grow into adulthood that populations failed to recover quickly enough after the devastating impact 65 million years ago.

 

A Meteorite Older Than Earth Discovered by Australian Geologists in outback Australia

Recently, the Desert Fireball Network of Curtin University traced the meteorites in Australian lake, Eyre. The total weight of meteorite is 1.7 Killo Gram. Its age is estimated around 4.5 billion years.

Photo: Curtin University/Desert Fireball Network

According to http://www.abc.net.au/ , recent discovery of meteorite plunged to Earth in the November. The team of Curtin University has been after this. However it was tracked later in remote spot in Australian Outback beside Lake Eyre.

Phil Bland, a geologist professor who is also a leader of team, extracted it from the soil by hand. He said,

“It was an amazing effort,” Bland said in a press release from the university. “We got there by the skin of our teeth.”

Professor Bland said. “It is older than the Earth itself. It’s the oldest rock you’ll ever hold in your hand.”

“It came to us from beyond the orbit of Mars, so in between Mars and Jupiter.”

Across WA and South Australia, a new observation of network of 32 remote cameras appears to be helping in finding meteorite.  The geologist and researchers spent on 3 days operations to get it. There were 2 researchers, an aerial spotter, quad bike, a drone and local aboriginal guides. It was very difficult to make observation from air due to stormy weather and rain.

The cameras (Desert Fireball Network) assisted in research area upto 500 meter. As per the researchers and geologists, the meteorite is a form of chondroitin. Or in other words, it is a stony meteorite. Early estimation is that it is 4.5 billion years old.

It is also observation by a few scientists that first Asteroid which stroke the Earth and became cause of dinosaurs extinction — It was broken up between Mars and Jupiter.

Reuters / NASA

The Cameras

The Desert Fireball Network records the picture of meteors during their falling. It is attached to a software which help in tracking direction, calculation of sped, landing zone and actual orbit of meteoric. It can tell the original body of the meteors from where it is coming. After finding the object, it can be further analyzed regarding its characteristics, chemical composition, or composition of actual body from where it has fallen apart. The scientists can observe the solar system through getting information from the observations and analysis of meteorite.

What is Meteorite?

Meteorite is a rocky fragment which has come from outer space from earth as a meteor. The Meteorite is consisted of 90% rock material and rest is based on iron and nickel. When any object or rock enters the earth atmosphere, it has to face various resistances on the way. Such as friction, environmental effects, chemical interaction, pressure. It can react or be affected by chemical interactions within atmosphere gases which make them heated or radiated. All these changes affect the object and make it in form of meteor. It falls on earth like a fireball. Because of this, it is also called shooting / falling star.

Only those meteorites survive which comes in a very large sizes. Most of the part becomes damaged or finished during atmospheric entry and on the way changes.

 

10 Simple Tests For Identifying Minerals

Minerals have a variety of physical and chemicals properties that can be evaluated using simple tests. The under mentioned checking method can tell us about mineral with simple laboratory tools and equipment. However, in some cases some tests can be dangerous for minerals and gemstones.

  1. Hardness
  2. Mohs Hardness Scale
  3. Magnetism
  4. Color
  5. Luster
  6. Streak
  7. Fluorescence
  8. Crystal Shape
  9. Specific Gravity
  10. Fracture
  1. Hardness

Hardness in any mineral tells us about resistance of a mineral. How much a mineral has an ability to resist against environment or changes? Minerals are formed by different durability level and characteristics. There are various levels of checking the hardness of a mineral. One can check the hardness of mineral with simple scratching with an hard tool on the surface of the mineral.

  1. Mohs Hardness Scale

Three is a list of hardness of common minerals. During checking of hardness test, it may destroy the mineral so care should be taken. The hardness of minerals and Mohs Hardness Scale are studied and examined used in laboratories .

  1. Magnetism

A pure Iron and magnetite (Fe3O4) are rocks which have magnetic effects. There are also some meteorites which has iron rich having magnetic effects. There are many minerals having richness of iron which are half magnetic and have magnetic susceptibility which can be measured as well.

  1. Color

We can judge the mineral or a gem through its colour. Colour can be observed by necked eye easily. But we cannot trust on colour regarding identification. A single mineral can be observed in various colours such as tourmaline, spinels, topaz etc

 

  1. Luster

Luster is another thing which interprets the mineral. A luster tells us how the light is reflected from a mineral’s surface. Luster can tell us if the mineral reflects metallic, shiny, g=glassy, silky, early or non metallic from surface. .

  1. Streak

Through streak we can identify the mineral through scratching its surface specially in soft minerals. After scratching, there remains a colour on the surface of the mineral. The streak of mineral can be different from the actual coloour of mineral also. This is very useful for the minerals having less than 7 hardness. However streak test can also destroy a mineral. Care should be maintained while doing this test.

  1. Fluorescence

— there are some minerals which have colour effects changes under different lights. For example if you throw a backlight in fluorite, or zinc mineral or Petroleum Quartz, they will glow in different colours. However mostly rocks and minerals cannot be fluorescent.

 


Fluorescent minerals from Baluchistan Petroleum Quartz

  1. Crystal Shape.

There are various types of crystals shapes which is formed by mineral’ atoms.  Shape results from the pattern formed by the atoms of a mineral when it is forming. Example is various shapes of quartz crystals.

  1. Specific Gravity

Specific Gravity means that what is the ratio of mineral mass in equivalent with equal volume water mass.

  1. Fracture

This is can tell weakness of crystal structure. For example when the miner picks mineral from mine in breakage form, it can tell the type of fracture. Whether the fracture is irregular or appears to be like a broken glass.