SCIENCE MAG

December 2020 Issue 12 Volume13 CALCITE A SCIENCE MAGAZINE

WELCOME TO CALCITE

TABLEOF CONTENTS 5 12 9 1 USES APPLICATION ADVANTAGES & HISTORY Real-life uses/product of DISADVANTAGES the application of the the mineral mineral in the field of earth A brief history of the Advantages and mineral and formation disadvantages of the science of the mineral 17mineral. 14 EXTRACTION & REFINING How to get calcite? PROPERTIES What are the properties of Calcite?

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HISTORY OF CALCITE A large percentage of the calcite in rocks was deposited in sedimentary environments; consequently, calcite is a constituent of several diverse sediments, sedimentary rocks, and their metamorphosed products. A minor amount of the Earth’s calcite is igneous origin; it is the chief constituent of the rare rock called carbonatite. Calcite also occurs widely in veins: some of the veins are wholly or largely calcite; others contain valuable ore minerals and are usually described as ore veins, even though calcite is the predominant constituent. 2 BRIEF HISTORY

A various color of calcite. HISTORY OF CALCITE The sedimentary rocks composed largely of calcite include limestones of chemical and biochemical origin and also limestones usually referred to as clastic because they consist of transported fragments of previously deposited, typically biogenetic materials. Travertine (also known as tufa), chalk, and micritic, respectively, are examples of these kinds of limestones. Many limestones have gained their mineralogical makeups and textures during diagenesis. Aragonite, the orthorhombic polymorph of CaCO3, was deposited and subsequently transformed into the calcite of some limestones; magnesian calcites that constitute some organic skeletal parts and cements of marine sediments were the precursors of the calcite of many other limestones. During diagenesis, most of the magnesian calcites were transformed into stable assemblages of rather pure calcite, often along with scattered grains of dolomite. The calcite of carbonatites is generally thought to have formed from dense H2O-CO2 fluids that in many ways are more like the volatile-rich fluids from which pegmatites are believed to have been deposited than the more “normal” magmas from which igneous rocks such as granites and basalt have consolidated. These rocks closely resemble marbles, and some masses of both marble and carbonatite were originally misidentified, one as the other. In most cases, the identities of the accessory minerals serve as ready criteria for differentiating between an igneous and metamorphic origin. BRIEF HISTORY 3

a) Showing the presence of travertine, a CaCO3 HISTORY OF CALCITE precipitate of calcite or aragonite, speleothem (cave formation), in southwestern Virginia, U.S. Calcite is deposited by solutions, either ordinary groundwater solutions or hydrothermal solutions associated with magmatic activities. Such calcite constitutes the cement for many clastic sediments—e.g., some sandstones—and also the calcite or aragonite of speleothems and of both calcite and calcific ore-bearing veins. b) Møn: chalk cliffs Calcite is deposited by solutions, either Chalk cliffs on the eastern coast of Møn island, Denmark. ordinary groundwater solutions or hydrothermal solutions associated with 4 BRIEF HISTORY magmatic activities. Such calcite constitutes the cement for many clastic sediments—e.g., some sandstones—and also the calcite or aragonite of speleothems and of both calcite and calcitic ore-bearing veins.

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USES OF CALCITE Marble is a metamorphic rock that forms when limestone is subjected to heat and The properties of calcite make it one of the pressure. A close examination of a broken most widely used minerals. It is used as a piece of marble will usually reveal obvious construction material, abrasive, agricultural cleavage faces of calcite. The size of the soil treatment, construction aggregate, calcite crystals is determined by the level of pigment, pharmaceutical and more. It has more metamorphism. Marble that has been uses than almost any other mineral subjected to higher levels of metamorphism will generally have larger calcite crystals. IN CONSTRUCTION IN ACID NEUTRALIZATION The construction industry is the primary consumer of calcite in the form of limestone and Calcite has numerous uses as a neutralizer of marble. These rocks have been used as acids. For hundreds of years, limestones and dimension stones and in mortar for thousands of marbles have been crushed and spread on years. Limestone blocks were the primary fields as an acid-neutralizing soil treatment. construction material used in many of the They are also heated to produce lime that has pyramids of Egypt and Latin America. Today, a much faster reaction rate in the soil. rough and polished limestone and marble are still an important material used in prestige architecture. Modern construction uses calcite in the form of limestone and marble to produce cement and concrete. These materials are easily mixed, transported, and placed in the form of a slurry that will harden into a durable construction material. Concrete is used to make buildings, highways, bridges, walls, and many other structures. AS LIMESTONE AND MARBLE Limestone is a sedimentary rock that is composed primarily of calcite. It forms from both the chemical precipitation of calcium carbonate and the transformation of shell, coral, fecal and algal debris into calcite during diagenesis. Limestone also forms as a deposit in caves from the precipitation of calcium carbonate 6 USES OF CALCITE

Calcite is used as an acid neutralizer in the AS CALCIUM CARBONATE chemical industry. In areas were streams are SORBENTS plagued with acid mine drainage, crushed limestone is dispensed into the streams to Sorbents are substances that have the ability to neutralize their waters. Calcium carbonate \"capture\" another substance. Limestone is often derived from high-purity limestones or treated and used as sorbent material during the marbles is used in medicine. Mixed with burning of fossil fuels. Calcium carbonate reacts sugar and flavoring, with sulfur dioxide and other gases in the combustion emissions, absorbs them, and These are the uses and products of Calcite prevents them from escaping to the atmosphere. calcium carbonate is made into chewable IN MONUMENTS AND tablets used in the neutralization of stomach STATUARY acids. It is also an ingredient in numerous medications used to treat digestive and other Marble is an attractive and easily worked rock ailments. that has long been used for monuments and sculptures. Its lack of significant porosity allows it to stand up well to freeze-thaw action outdoors, and its low hardness makes it an easy stone to work. It has been used in projects as large as the pyramids and as small as a figurine. It is widely used as cemetery markers, statues, mantles, benches, stairways, and much more. OTHER USES In a powdered form, calcite often has an extremely white color. Powdered calcite is often used as a white pigment or \"whiting.\" It is a primary ingredient in whitewash, and it is used as an inert coloring ingredient of paint. Pulverized limestone and marble are often used as a dietary supplement in animal feed.. Small amounts of calcium carbonate are often added to their feeds to enhance their calcium intake. Calcite has a hardness of three on the Mohs scale, and that makes it suitable as a low-hardness abrasive. Its low hardness makes it an effective cleaning agent that does not damage the surface being cleaned. USES OF CALCITE 7 FEATURED STORIES | 43

OTHER USES Pulverized limestone is also used as a mine safety dust. This is a nonflammable dust that is sprayed onto the walls and roofs of underground coal mines to reduce the amount of coal dust in the air (which can be an explosion hazard). The mine safety dust adheres to the wall of the mine and immobilizes the coal dust. Its white color aids in illumination of the mine. It is the perfect material for this use. CALCITE: A CARBON DIOXIDE REPOSITORY Carbon dioxide is an important gas in Earth's environment. In the atmosphere it serves as a greenhouse gas that works to trap and hold heat near the surface of the planet. The process of limestone formation removes carbon dioxide from the atmosphere and stores it away for long periods of time. This process has been occurring for millions of years - producing enormous volumes of stored carbon dioxide. When these rocks are weathered, used to neutralize acids, heated to make cement or metamorphosed severely, some of their carbon dioxide is released and returned to the atmosphere. All of these processes of limestone formation and destruction have an impact on Earth's climate. Some sightings of calcite at the caves and deserts. 8 USES OF CALCITE

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OA DF VCAANLTCAI TGEE S1LOWER CARVING GREENHOUSE AS Limestone is a somewhat soft rock form; it can be carved into shapes or shapes can IMPACT be carved into it much easier than many 2CaCO3 into plastic products other rock forms. has also been shown to lower IN PLASTICS the greenhouse gas impact of the end-use product Reduces petrochemical and energy usage during the manufacturing process 4ELEGANCE Water treatment A fireplace hearth made of Helps to remove excessive iron from 3sandstone can create a water, reduce water pH definitive focal point in a Good for ponds room. The \"look\" of Increases nutrient availability, fish limestone can increase the growth and alkalinity. home value because it is considered an impressive and sophisticated stone 56DURABILITY AND DEPENDABILITY Limestone is a great natural stone for durability. It has been used in numerous important buildings such as museums, schools, churches, courthouses 7and more. It also has a rich history for structures in the Philippines that are still standing today. ADVANTAGES AND 10 DISADVANTAGES

D I S A D V A N T A G E SGROUNDWATER LIMESTONE QUARRIES CAN BE SEEN FROM Groundwater quality can be affected by LONG DISTANCES. quarrying limestone by increasing POROUS AND SOFT O F C A L C I T Esediment and accidental spills directly Limestone is a porous rock which into the aquifers. means it has many tiny holes throughout the material. 1AFFECTS RESPIRATORY DUST SYSTEM AND SKIN one of the most visible impacts 2IRRITATION associated with limestone quarrying Affects lungs when inhaled and due to the drilling, crushing and causes irritation to eyes, nose, skin screening of the rock.This airborne and throat. dust can travel long distances from a mining site and affect urban and rural 43SUBSIDENCE residential areas downwind. Limestone is often mined from a quarry. This creates caves which can become weak and collapse. Underground mining of limestone can cause a cascading environmental impact. 56HABITAT DESTRUCTION As rock is removed by quarrying, any cave passages — and the habitat it provides — are destroyed. Animals that inhabit these areas that are 7mobile will be able to find new habitats to survive. Those species that have adapted to such deep cave zones will simply perish.  FEATAUDREVDANSTTOARGIEESS |A4N3D 11 DISADVANTAGES

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IN GEOLOGY AND Geology and Oceanography OCEANOGRAPHY All natural waters contain dissolved calcium and carbon dioxide, and their concentration is especially high in seawater. Many marine animals including corals, snails, clams, algae, and microscopic plankton use calcite and aragonite to form their shells and hard parts. Microorganisms can also indirectly lead to the precipitation of calcite as they alter the chemistry of the fluids in which they live. Once formed, calcite is easily dissolved and its component ions released to precipitate elsewhere. As a consequence, calcite is not only the main mineral of limestone rocks and marble (metamorphosed limestone), but also a common accessory component of sandstone and siltstone rocks. Helps to remove excessive iron from water, reduce water pH. In the atmosphere it serves as a greenhouse gas that works to trap and hold heat near the surface of the planet. The process of limestone formation removes carbon dioxide from the atmosphere and stores it away for long periods of time. Calcite is used and good for contruction materials, soil treatment, pharmaceutical, pigment, coal mine, animal feed, plastic industry, paint industry and paper industry. 13

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EXTRACTION ANDREFINING EXTRACTING AND Surface treatment of GCC is another aspect of PROCESSING GROUND adding value to the basic material. Such coatings CALCIUM CABORNATE aim to match the surface tension of calcium carbonate fillers with that of the compounds Extracted by mining or quarrying. It can be (e.g. thermoplastics) in which they are underground mining or surface mining. Pure incorporated. calcium carbonate can be produced from marble, or it can be prepared by passing carbon dioxide into a solution of calcium hydroxide. After quarrying or mining, further treatment is required to process natural calcium carbonates (and dolomite, which is very similar) of the highest quality, known generically as Ground Calcium Carbonate (GCC).The production process maintains the carbonate very close to its original state, ending up in a finely ground product delivered either in dry or slurry form (water based suspension). Generally, the processing includes washing, On the top: Surface mining At the bottom sorting of undesirable contaminants, grinding, size classification of particles and possibly Underground Mining. drying. Depending on the circumstances and intended uses, the order and necessity of those different steps vary. At the outlet of the process, the material is delivered in bags or in bulk when dry, or as bulk tankers for slurries by road or rail. EXTRACTION AND 15 REFINING

EXTRACTING AND PROCESSING PRECIPATION CALCIUM CABORNATE The use of recarbonisation method of PCC production above: Silos used for storing calcium (precipitated calcium cabornate) where limestone is converted into calcium oxide (lime) and carbon dioxide by calcination at high temperatures. After calcination the lime is slaked with water and the resulting milk of lime is purified and re-carbonised with the carbon dioxide obtained directly from the calcination process. carbonate prior to delivery by bulk tanker to the customer This produces a water-based suspension of CaCO3. A cake comprising upto 60% solid matter (depending on particle diameter) is then obtained by filtration. This filter cake is then dried and subsequently disagglomerated in grinders. Depending on the chemical composition of the milk of lime used and on the purifying stages during production, food and pharmaceutical grades as well as technical grades can be produced. above: Scanning Electron Microscope of ground Coated grades of PCC are also produced by calcium carbonate (GCC) introducing fatty acids or other additives at the suspension stage prior to filtration. beside: Scanning Electron Microscope of scalenohedral precipitated calcium carbonate (PCC) 16 EXTRACTION AND REFINING

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PROPERTIES OF CALCITE PROPERTIES OF CALCITE Calcite is colourless or white when pure but may be The previously described fact that calcite of almost any colour—reddish, pink, yellow, effervesces vigorously with dilute hydrochloric greenish, bluish, lavender, black, or brown—owing (muriatic) acid distinguishes calcite from to the presence of diverse impurities. It may be dolomite, which it tends to resemble in both transparent, translucent, or opaque. Its lustre appearance and occurrence. (Dolomite ranges from vitreous to dull; many crystals, effervesces only when powdered and with only a especially the colourless ones, are vitreous, slow, smoldering action.) whereas granular masses, especially those that are fine-grained, tend to be dull. Calcite is number 3 on the Mohs hardness scale; thus, it can be scratched readily by a knife blade or geologic pick. It has a specific gravity of 2.71. Three perfect cleavages give calcite its six-sided polyhedrons with diamond- shaped faces; the angles defining the faces are 78° and 102°. The three important crystal habits (distinctive shapes of the mineral) of calcite are: (1) prismatic (both short and long), (2) rhombohedral, and (3) scalenohedral. Twinning is very common and may be of secondary origin in crystalline limestones. Some calcites fluoresce under ultraviolet light; some are also triboluminescent (luminescent when scratched). When light passes through some minerals, it is split into two rays that travel at different speeds and in different directions. This phenomenon is known as birefringence. The difference between the velocities is especially notable in calcite, and consequently crystals of a colourless variety— sometimes called Iceland spar—exhibit double refraction that can be observed with the naked eye. 18 PROPERTIES OF CALCITE In rocks made up predominantly of calcite, the mineral is typically granular, with grains ranging from those discernible only under a microscope to those that are a few millimetres in greatest dimension. The colour of most of these rocks is gray or tan, but some calcite marbles are white and a few are multicoloured.

SOURCES OF INFORMATION https://www.britannica.com/science/calcite https://geology.com/minerals/calcite.shtml https://www.hunker.com/13411528/advantages-disadvantages-of-limestone https://www.limestone.com/about-us/limestone-learning-center/5-top-benefits- of-using-limestone-in-your-home-design/ https://natureofmarble.com/pros-cons-calcite-countertops/ https://blog.impactplastics.co/blog/reduced-environmental-impact-through-use- of-calcium-carbonate https://nj.gov/health/eoh/rtkweb/documents/fs/4001.pdf http://www.calcium-carbonate.org.uk/calcium-carbonate/caco3-processing.asp FOR IMAGES https://www.gemstonebuzz.com/gemstone/calcite/ Google Images Crisjay Mari V. Brizuela SC1L 19 SOURCES

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