Petrographic International Pty Ltd in Brisbane, Queensland, Australia | Home improvement

Petrographic International Pty Ltd

Locality: Brisbane, Queensland, Australia

Phone: +61 7 3284 0020

Address: 28 Cameron Street 4019 Brisbane, QLD, Australia

Website: http://www.geochempet.com

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25.01.2022 After analyzing a number of diamonds, geologists have discovered "young diamonds" which will undoubtedly shake up the diamond industry. A study of 26 diamonds, formed under extreme melting conditions in the Earth's mantle, found two populations, one of which has geologically 'young' ages. The results show that certain volcanic events on Earth may still be able to create super-heated conditions previously thought to have only existed early in the planet's history before it co...oled. The findings may have implications for diamond prospecting. Diamonds can be categorized by their inclusions: minerals trapped within the carbon crystal structure that give clues about the conditions and the rocks in which they formed. The studied diamonds contain harzburgitic inclusions, a type of peridotite the most common rock in Earth's mantle which have experienced extreme temperatures and undergone very large amounts of melting. Gareth Davies, co-author of the study, commented, "This is a fascinating insight into the inner workings of planet Earth. While young diamonds are formed in other types of rocks and conditions in the mantle, it's very unexpected to find harzburgitic diamonds linked to relatively recent geological activity. As harzburgitic rocks are important markers for diamond prospecting, the findings may have implications for the geological environments where we look for new diamond mines." Source: http://www.geologyin.com

21.01.2022 Petoskey stone is a rock and a fossil, often pebble-shaped, that is composed of a fossilized rugose coral, Hexagonaria percarinata. The name Petoskey Stone likely came about because it was found and sold as a souvenir from the Petoskey area. The name Petoskey appears to have originated late in the 18th century. Its roots stem from an Ottawa Indian legend. In 1965, Petoskey stone was named the state stone of Michigan. It is a fossil colonial coral that lived in the warm Mich...igan seas during the Devonian time around 350 million years ago. The name Hexagonaria (meaning six sides) percarinata was designated by Dr. Edwin Stumm in 1969 because of his extensive knowledge of fossils. This type of fossil is found only in the rock strata called the Gravel Point Formation. This formation is part of the Traverse Group of the Devonian Age. The stones were formed as a result of glaciation, in which sheets of ice plucked stones from the bedrock, grinding off their rough edges and depositing them in the northwestern (and some in the northeastern) portion of Michigan's lower peninsula. In those same areas of Michigan, complete fossilized coral colony heads can be found in the source rocks for the Petoskey stones Source: http://www.geologyin.com

19.01.2022 The Carlin-type gold deposits in Nevada, USA, are the origin of five percent of the global production and 75 percent of the US production of gold. In these deposits, gold does not occur in the form of nuggets or veins, but is hidden together with arsenic in pyrite, also known as ‘fool’s gold’. A team of scientists from the Helmholtz Centre Potsdam German Research Centre for Geosciences GFZ has now shown experimentally, for the first time, that the concentration of gold ...directly depends on the content of arsenic in the pyrite. The results were published in the journal Science Advances. In the Earth’s crust, the element gold occurs in concentrations of 2.5 parts per billion (ppb). In order to mine it economically, the gold concentration must be thousands of times higher and it must be found in a focused area close to the surface. In the gold deposits of the Carlin-type, the gold in the rock is not visible to the human eye. Instead, the ‘invisible’ gold occurs in tiny pyrite rims that grow on older ‘fool’s gold’ grains which originate from sedimentary rocks. Recommended: States With Gold : Where Are Gold Mines In The United States? Read more : http://www.geologypage.com//resolving-the-invisible-gold-p Follow us: @geologypage on Twitter | geologypage on Facebook

18.01.2022 This is a great editorial by Quora and then reprinted by mentalfloss. A little humour for a Monday. Enjoy your week.

13.01.2022 All over the world, spectacular fossils have frequently been found preserved inside solid, roughly spherical rocks called "concretions." From geologists to casual observers, many have wondered why these hardened masses of carbonate formed around dead organisms, with round shapes and sharp boundaries with the surrounding material, typically in marine mud and mudstone. Several important questions regarding concretions have long puzzled scientists. What conditions cause them to ...form? How long do they take to grow? Why do they stop growing? Why are they so distinct from the surrounding rock or sediments? Now, researchers led by Nagoya University have developed a method to analyze concretions using L-shaped "cross-plot diagrams" of diffusion and growth rate, reported in a new study published in Scientific Reports. With this method, they analyzed dozens of concretions from three sites across Japan and compared them with concretions from England and New Zealand. Read more at http://www.geologyin.com//researchers-resolve-formation-me

08.01.2022 Discovered by chance, the secret Mexican crystal caves big enough to drive a car through The Naica Mine of the Mexican state of Chihuahua, is a working mine that is best known for its extraordinary selenite crystals. Located in Naica in the municipality of Saucillo, the Naica Mine is a lead, zinc and silver mine operated by Industrias Peñoles, Mexico's largest lead producer. Caverns discovered during mining operations contain crystals of selenite (gypsum) as large as 4 feet (...1.2 m) in diameter and 50 feet (15 m) long. Formation of the crystals Naica lies on an ancient fault and there is an underground magma chamber below the cave. The magma heated the ground water and it became saturated with minerals, including large quantities of gypsum. The hollow space of the cave was filled with this mineral-rich hot water and remained filled for about 500,000 years. During this time, the temperature of the water remained very stable at over 50 C (122 F). This allowed crystals to form and grow to immense sizes. Read more at http://www.geologyin.com//the-huge-cave-mines-at-naica-mex

04.01.2022 Fossils unearthed from an Ethiopian site not far from where the famous hominid Ardi’s partial skeleton was found suggest that her species was evolving different ways of walking upright more than 4 million years ago. Scientists have established that Ardi herself could walk upright (SN Online: 4/2/18). But the new fossils demonstrate that other members of Ardipithecus ramidus developed a slightly more efficient upright gait than Ardi’s, paleoanthropologist Scott Simpson and colleagues report in the April Journal of Human Evolution. The fossils, excavated in Ethiopia’s Gona Project area, are the first from the hominid species since 110 Ar. ramidus fossils, including Ardi’s remains, were found about 100 kilometers to the south (SN: 10/24/09, p. 9). #geology #sciencenewsmagazine #geology #geochempet http://ow.ly/Ycuj30oge85

04.01.2022 Punakaiki Pancake Rocks, New Zealand | #Geology #GeologyPage #NewZealand The Pancake Rocks are a very popular tourist destination at Dolomite Point south of the main village. The Pancake Rocks are a heavily eroded limestone area where the sea bursts through several vertical blowholes during high tides. Together with the 'pancake'-layering of the limestone (created by immense pressure on alternating hard and soft layers of marine creatures and plant sediments), these form the main attraction of the area. REF: Geologypage

03.01.2022 Isn't this tone just beautiful! Petoskey stone A Petoskey Stone is a rock and a fossil composed of a fossilized rugose coral, Hexagonaria percarinata, which is often pebble-shaped. Such stones were formed as a result of glaciation, where sheets of ice plucked stones from the bedrock, grinding off their rough edges and depositing them in the lower peninsula of Michigan’s northwest (and some in the northeast). Complete fossilized coral heads can be found in the source rocks for... the Petoskey stones in the same areas of Michigan. Petoskey stones are found in the Traverse Group’s Gravel Point Formation. They are fragments of an originally deposited coral reef during the Devonian period. When dry, the stone resembles ordinary calcareous but the distinctive mottled pattern of six-sided coral fossils emerges when wet or polished using lapidary techniques. It is sometimes turned into objects of decoration. There are also other forms of fossilized coral in the same location. Petoskey stones can be found in Michigan on different beaches and inland locations, with many of the most popular being those around Petoskey and Charlevoix. During the winters, the frozen lake ice movement acting on the shore is thought to turn over stones at the shore of Lake Michigan, exposing new Petoskey stones at the edge of the water every spring. Also present in the fossil records of Iowa, Indiana, Illinois, Ohio, New York and locations in Canada, Germany, England, and Asia is the type of coral that forms the basis of Petoskey Stones. Read more : http://www.geologypage.com//petoskey-stone-what-is-petoske Follow us: @geologypage on Twitter | geologypage on Facebook Read more : http://www.geologypage.com//petoskey-stone-what-is-petoske Follow us: @geologypage on Twitter | geologypage on Facebook

01.01.2022 Zircon crystals, composed of silicon, oxygen and zirconium, are some of the oldest artefacts available predating even the most ancient of rocks that formed 4 billion years ago to researchers studying the early Earth conditions. Image credit: Parent Géry via Wikimedia.org, CC BY-SA 3.0. When did life on Earth begin? Scientists have dug down through the geologic record, and the deeper they look, the more it seems that biology appeared early in our planet’s 4.5-billion-year ...history. So far, geologists have uncovered possible traces of life as far back as 3.8 billion years. Now, a controversial new study presents potential evidence that life arose 300 million years before that, during the mysterious period following Earth’s formation. The clues lie hidden in microscopic flecks of graphitea carbon mineraltrapped inside a single large crystal of zircon. Zircons grow in magmas, often incorporating other minerals into their crystal structures of silicon, oxygen, and zirconium. And although they barely span the width of a human hair, zircons are nearly indestructible. They can outlast the rocks in which they initially formed, enduring multiple cycles of erosion and deposition. In fact, although the oldest rocks on Earth date back only 4 billion years, researchers have found zircons up to 4.4 billion years old. These crystals provide a rare glimpse into the first chapter of Earth’s history, known as the Hadean eon. They are pretty much our only physical samples of what was going on on the Earth before 4 billion years ago, says Elizabeth Bell, a geochemist at the University of California, Los Angeles (UCLA), and lead author of the new study, published online today in the Proceedings of the National Academy of Sciences. Read more at http://www.geologyin.com//41-billion-year-old-crystal-may-