The Science of Gemstones [Guest Article]

Gemmology, also known as the science of gemstones, is the study of precious gemstones. It mainly focuses on identifying gemstones, confirming its authenticity, evaluating the quality, determining the origin, and disclosing the treatment used for the gemstone. A major part of it requires distinguishing between natural gemstones and synthetic counterparts and imitations. Earlier it was difficult to identify synthetic crystals but that is not much of a problem these days. Gemmologists also find out the treatment used for gemstones as it directly influences the price of a gemstone. In most cases, original gemstones undergo physical and chemical treatment to enhance the aesthetic appeal.

Origins of Some Famous Gemstones

Gemmologists have a set of skills to identify where exactly the gemstone was mined from. Gemstones usually have certain characteristics typical of the origin. Many consumers also have a special preference for gemstones belonging to a particular origin. for example, Blue sapphire from Kashmir, Rubies from Burma, Emerald from Columbia have always been in great demand. Such gemstones cost comparatively more than similar gemstones from other localities.

 Kashmir sapphires are valued as they contain the best specimens. These gemstones are seen to have an excellent cornflower blue tint. Most describe the hue as ‘blue velvet’. While some Burmese and Ceylonese sapphires also come relatively close in quality, only the Kashmir Sapphire continues to rule the Sapphire World. 

Difference Between Synthetic and Natural Gemstones

Classification of gemstones is necessary when dealing with them. Natural gemstones are the ones that grow naturally in nature over the years. On the other hand, "Synthetic" gemstones are those which exactly mimic natural gemstones but are created by man in a laboratory. They possess the same physical, chemical, and optical properties as the natural gemstone. The most common of these are synthetic Diamonds, Synthetic Sapphires, and synthetic Quartz. A layman can not identify the difference between synthetic and natural gemstone. Then comes the “Imitation gemstones” which basically have a similar appearance as the original gemstones. For example, blue glass, polystyrene, or zirconia. The most popular impression of a diamond is zirconia (synthetic ZrO2). Zirconia cannot be easily distinguished from a diamond in the same shape.

How to check the quality and related certifications

Gemstones are not only used for Jewelry purposes but also for their astrological benefit and healing properties. It is crucial to be assured of the authenticity of the gemstone to avoid any negative impact. Many dealers trade fake gemstones in the market to maximize profit. One should be aware of the tricks used by such dears to dupe their customers. It is always desirable to get a gemstone from a reputed seller who is happy to answer all your queries with utmost honesty. There is no better way than to invest your hard-earned money in a real, lab certified gemstone as it ensures the best value for your money. When buying a rare and expensive gemstone that too of a popular origin, one should be extra cautious and must look for certificates issued by the reputed gem labs like IGI, GTL, GIA, GRS, etc.

Pricing Factors of Gemstones

Before choosing a gemstone, it is necessary to know how a minor variation in quality, size, or origin can bring a huge variation in the gemstone price. Color, clarity, cut and carat weight are some of the key price grading factors. If you are planning to buy a gemstone for astrological use, it is important to ensure that the gemstone is natural and free from any sort of treatment (heating, chemical treatment, dying, etc.). Selecting a gemstone from a reputed origin is one good way to ensure quality.

Where does energy in U.S come from? [Guest Article]

From burning firewood to using electricity from renewable sources, the home energy landscape has drastically changed over the last 150 years. This article and infographic explore the history of energy use and what the sustainable future may look like.

We no longer have to gather firewood for our wood-burning stoves to keep us warm at night, but there are a variety of energy sources used in each home. Most homes in the U.S. run on either electricity or natural gas, or a combination of both, but homeowners may also employ solar panels or even residential wind-powered solutions too. 

Looking at the charts below, you can see that energy consumption has grown significantly each year and in 2018, it hit an all-time high. However, you’ll notice some changes in the way we use each energy source. Coal is the only energy source below that has suffered a decline and renewable energy has recently surpassed nuclear energy. As new technologies are developed, we are finding new ways to meet the increased energy demand. The future of energy consumption will look very different than it does today.

Where does energy in US come from?

By no surprise, oil has been the largest and most popular source of energy. Since the 1950s, oil and natural gas were used to heat homes. Now in 2020, you know that petroleum is used for many other reasons and industries, from powering our cars to packaging products in plastic. 

Although coal was another popular source of energy, it has been on the decline for the last few decades. It’s less efficient than other sources and negatively impacts the environment. To answer that problem, the U.S. has been investing in renewable energy sources. Wind, solar, and geothermal energy are proving to be great resources for a clean future.

Are renewables the future?

Although only 11% of U.S. energy production comes from renewable sources, it is expected to grow. Solar, wind, and geothermal technology energy are three of the top sources for renewable energy. Among those, wind is the fastest growing and judging from the production map, it has wide geographic potential as well. Geothermal energy, which uses underground temperatures to transfer energy, is becoming a popular alternative for home heating and cooling. Of course, residential solar panels are gaining wide adoption as well. As renewable energy options become more available, the energy consumption landscape is likely to move toward a more sustainable future. 

This infographic from The Zebra walks through the history of energy use, where energy is produced, and what the future of energy may look like.

Author bio: Amanda Tallent is a writer who covers everything from business to lifestyle. She creates content to help people live more informed and confident lives. 

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Guest Blog: How Speleothems Are Used To Determine Past Climates?

About author: Alex Graham is an undergraduate student at University of Newcastle, Australia. He is interested in Geology as a whole but his major interests include fluvial processes, karst systems and ocean science. During his visit to New Zealand, he has obeserved the glow worms in Waitomo Caves and spelunking in Nikau Caves.

Speleothems, more commonly known as stalactites or stalagmites, consist of calcium carbonate (calcite or aragonite) crystals of various dimensions, ranging from just a few micrometers to several centimetres in length, which generally have their growth axis perpendicular to the growth surface. Speleothems are formed through the deposition of calcium carbonate minerals in karst systems, providing archives of information on past climates, vegetation types and hydrology, particularly groundwater and precipitation. However, they can also provide information on anthropogenic impacts, landscape evolution, volcanism and tectonic evolution in mineral deposits formed in cave systems.

Stalagmite Formation

Rainfall containing carbonic acid weathers the rock unit (generally either limestone or dolomite) and seeps into the cracks, forming caverns and karst systems. The groundwater, percolating through such cracks and caverns, also contains dissolved calcium bicarbonate. The dripping action of these groundwater droplets is the driving force behind the deposition of speleothems in caves.

Core drilling of an active stalagmite in Hang Chuot cave.

Speleothems are mainly studied as paleoclimate indicators, providing clues to past precipitation, temperature and vegetation changes over the past »500,000 years. Radioisotopic dating of speleothems is the primary method used by researchers to find annual variations in temperature. Carbon isotopes (d^13C) reflect C3/C4 plant compositions and plant productivity, where increased plant productivity may indicate greater amounts of rainfall and carbon dioxide absorption. Thus, a larger carbon absorption can be reflective of a greater atmospheric concentration of greenhouse gases. On the other hand, oxygen isotopes (d^8O) provide researchers with past rainfall temperatures and quantified levels of precipitation, both of which are used to determine the nature of past climates.

Stalactite and stalagmite growth rates also indicate the climatic variations in rainfall over time, with this variation directly influencing the growth of ring formations on speleothems. Closed ring formations are indicative of little rainfall or even drought, where-as wider spaced ring formations indicate periods of heavy rainfall or flooding. These ring formations thus enable researchers to potentially predict and model the occurrence of future climatic patterns, based off the atmospheric signals extrapolated from speleothems. Researchers also use Uranium –Thorium radioisotopic dating, to determine the age of speleothems in karst formations. Once the layers have been accurately dated, researchers record the level of variance in groundwater levels over the lifetime of the karst formation. Hydrogeologists specialise in such areas of quantitative research. As a result, speleothems are widely regarded as a crucial geological feature that provide useful information for researchers studying past climates, vegetation types and hydrology.


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The Messinian Salinity Crisis

You will have heard of The Messinian Salinity Crisis no doubt. From learned articles, geology textbooks, probably lectures at your college or University. Or possibly not. This was not always the hot topic it is now. In fact, the very idea of this happening, was for a while, challenged, even ridiculed. It seemed too incredible that this could happen as it did and Dessication/Flood theories took time to gain traction. But, if you had heard about it, you would remember that The Messinian Salinity Crisis, was a time when the Mediterranean Sea, very much as we know it today, evaporated – dried out, almost completely.

You will have heard of the rates of desiccation, influx and yet more desiccation, repeated in endless cycles over tens, even hundreds of thousands of years. On a human temporal scale, this would have been a long drawn out affair, covering a time hundreds of generations deep, more than the span of Homo sapiens existence. In Geologic terms however, it was a string of sudden events. Of incredibly hot and arid periods followed by rapid ingress of waters, either via spillways through what is now modern day Morocco and the southern Iberian peninsular, or headlong through a breach in the sill between the Pillars of Heracles, the modern day Straights of Gibraltar.

There were prolonged periods of dessication, of desolate landscapes beyond anything seen today in Death Valley or The Afar Triangle. These landscapes were repeatedly transgressed by brackish waters from storm seasons far into the African and Eurasian interiors, or the Atlantic, and these in turn dried out. Again and again this happened. It had to be so because the vast deposits of rock salt, gypsum and anhydrites could not have been emplaced in a single evaporite event. The salt deposits in and around the Mediteranean today represent fifty times the current capacity of this great inland sea. You may have heard too of the variety of salts production, as agglomerating crystals fell from the descending surface to the sea floor, or as vast interconnected hypersaline lakes left crystalline residues at their diminishing margins, as forsaken remnant sabkhas, cut off from the larger basins, left behind acrid dry muds of potassium carbonates – the final arid mineral residue of the vanished waters.

Just under six million years ago, Geologic processes isolated what was left of the ancient Tethys ocean, the sea we know as the Mediterranean, home to historic human conflicts and marine crusades of Carthage, Rome, Athens and Alexandria, a Sea fringed by modern day Benidorm, Cyprus, Malta and Monaco. At a time 5.96 million years ago – evaporation outpaced replenishment. Indeed, just as it does today, but without the connecting seaway to replenish losses. Inexorable tectonic activity first diverted channels, then – sealed them. Cut off from the Atlantic in the West, water levels fell, rose briefly and fell again, and again. The mighty Nile - a very different geophysical feature of a greater capacity than today, and the rivers of Europe cut down great canyons hundreds and thousands of metres below present Eustatic sea and land surface levels, as seismic cross sections show in staggering detail. The cores taken at depth in the Mediterranean, show Aeolian sands above layers of salt, fossiliferous strata beneath those same salts, all indicating changing environments. The periods of blackened unshifting desert varnished floors and bleached playas, decades and centuries long, were punctuated often by catastrophic episodes, with eroded non conformable surfaces of winnowed desert pavement, toppled ventifracts, scours and rip up clasts. Species of fossilised terrestrial plant life, scraping an arid existence have been found, thousands of meters down, in the strata of the Mediterranean sea floor.
 

There is much evidence too, in the uplifted margins of Spain, France, and Sicily, of those hostile millennia when the sea disappeared. Incontrovertible evidence, painstakingly gathered, analysed and peer reviewed, demonstrates via the resources of statistical analysis, calculus and geophysical data that the Messinian Salinity Crisis was a period during the Miocene wherein the geology records a uniquely arid period of repeated partial and very nearly complete desiccation of the Mediterranean Sea over a period of approximately 630,000 years. But for the Geologist, the story doesn’t end there. The Geologists panoptic, all seeing third eye, sees incredible vistas and vast panoramas. Of a descent from the Alpine Foreland to the modern day enclave of Monaco, gazing out southwards from a barren, uninhabited and abandoned raised coast to deep dry abyssal plains, punctuated by exposed chasms, seamounts and ridges, swirling and shifting so slowly in a distant heat haze. A heat haze produced by temperatures far above any recorded by modern man and his preoccupation with Global Warming. An unimaginable heat sink would produce temperatures of 70 to 80 degrees Celsius at 4000M depth within the basins. 

Looking down upon this Venusian landscape, the sun might glint on remaining lakes and salt flats so very far away and so very much farther below. Hills and valleys, once submerged, would be observed high and dry – from above, as would the interconnecting rivers of bitter waters hot enough to slowly broil any organism larger than extremophile foraminifer. All this, constantly shimmering in the relentless heat. Only the imagination of the geologist could see the vast, hellish, yet breathtaking landscape conjured up by the data and the rock record. And finally, the Geologist would visualise a phenomenon far greater in scope and magnitude than any Biblical flood – The Zanclean Event.

Also known as The Zanclean Deluge, when the drought lasting over half a million years was finally ended as the Atlantic Ocean breached the sill/land bridge between Gibraltar and North West Africa. Slowly perhaps at first until a flow a thousand times greater than the volumetric output of the Amazon cascaded down the slopes to the parched basins. Proximal to the breach, there would be a deafening thunderous roar and the ground would tremor constantly, initially triggering great avalanches above and below the Eustatic sea level as the far reaching and continuous concussion roared and rumbled on, and on, and on. For centuries great cataracts and torrents of marine waters fell thousands of metres below and flowed thousands of kilometers across to the East. Across to the abyssal plains off the Balearics, to the deeps of the Tyrrhenian and Ionian seas, into the trenches south of the Greek Islands and finally up to the rising shores of The Lebanon. The newly proximal waters to the final coastal reaches and mountains that became islands, must have had a climatological effect around the margins of the rejuvenated Mediterranean. Flora and Fauna both marine and terrestrial will have recolonised quickly. Species may have developed differently, post Zanclean, on the Islands. And in such a short period, there must surely have been earthquakes and complex regional depression and emergence. Isostacy compensated for the trillions of cubic meters of transgression waters that now occupied the great basins between the African and Eurasian plates, moving the land, reactivating ancient faults and within and marginal to the great inland sea, a region long active with convergent movements of a very different mechanism.

Hollywood and Pinewood have yet to match the imagination of the Earth Scientist, of the many chapters of Earths dynamic history held as fully tangible concepts to the men and women who study the rocks and the stories they tell. The movies played out in the mind of the geologist are epic indeed and – as we rightly consider the spectre of Global Warming, consider too the fate of future populations (of whatever evolved species) at the margins of the Mediterranean and the domino regions beyond, when inexorable geologic processes again isolate that benign, sunny holiday sea. Fortunately, not in our lifetime, but that of our far off descendants who will look and hopefully behave very differently from Homo Sapiens.

Note: This blog is written and contributed by Paul Goodrich. You can also contribute your blog or article on our website. See guidelines here.