how natural gemstones form?
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It depents on the gem, of course.  Most of the ones people think of as gems, such as diamonds, sapphires &c., form as high-temperature, high-pressure phases in deep molten rock.  They don't necessarily take a long time to crystallize either.  These phases aren't stable in cooler melts, though,  so the problem is to quickly get them to the surface from their formation depths.  Some volcanic eruptions do this.  Diamonds have to come all the way from the mantle to near the surface in minutes.\n\nOther gems can form near or at the surface.  Opal, for instance, is formed by precipitation of silica from groundwater.
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"Heating of gemstones to enhance their color goes back centuries. It is considered a natural type of treatment since the process is basically a continuation of the processes that occur in the ground. The stone is heated to a very high temperature, which causes the inclusions (ref. Why Gemstones Have Color in Colored Gemstones 101) to reform themselves and improve the color by making either darker, lighter, more intense, or of a different color. It has been properly stated that without heat treatment the world would be without many colored gemstones. Because colored gemstones occurring in the colors we see are very rare. But heating can take an off-color stone and turn it into a beautiful gemstone. So don't be worried about heat treatment.\n\nCan I wear it everyday?: Heat treatment, for the most part, is permanent. As in the case of the tanzanite shown above. This stone is a brown color coming out of the ground. But turns a beautiful blue/purple (shown at left) after heating. The few exceptions would be kunzite which will tend to fade from its medium pink color to light pink and then colorless in daylight (which is why its called the midnight stone), and yellow sapphire, which can also fade when exposed to direct sunlight.\n\nWhat does this treatment do to the stone?: Basically, it rearranges the atoms in the gemstone. Sometimes, as in the case of ruby, the stone is heated almost to a point of melting, which lets the aluminum oxide in the stone reform to what is basically a new crystal structure. This lets the chromium reform to give off a better color of red. The same can apply to a type of sapphire known as gouda sapphires. These are milky white sapphires that turn blue, and account for many of the promotional quality sapphires out on the market today."\n\n"Heat treatment, for the most part, is permanent. As in the case of the tanzanite shown above. This stone is a brown color coming out of the ground. But turns a beautiful blue/purple (shown at left) after heating. The few exceptions would be kunzite which will tend to fade from its medium pink color to light pink and then colorless in daylight (which is why its called the midnight stone), and yellow sapphire, which can also fade when exposed to direct sunlight."\n\n"Through heat treatment at 500+ degrees celcius the rough tanzanite crystals turn their beautiful purplish-blue color. The rough tanzanite gems are then faceted into various shapes and then marketed to dealers who wholesale the finished gems to jewelry manufacturers and retailers. Tanzanite colors occur in various shades of gray, brown, violet, blue, reddish-purple, and tints of green."\n\n"The raw uncut tanzanite is put in a furnace or oven and brought near its melting point, then held there at that temperature for a period of time, inducing the stone to darken in color as it would in the earth if left to its own. This process may sound simple, but it is far from being an easy or foolproof technique. It is quite possible in this heat treatment process to have the tanzanite melt or overcook, leaving you with a worthless pile of rubble."
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Rocks don't grow, but crystals do.  However, crystals only grow when they are imersed in the medium that contains its essential elements. You should measure it over time. It would be more accurate and convincing than just by looking at it.
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A gemstone / birth stone is a collective term for all ornamental stones that possess attributes like beauty, rarity, durability.Astral gems, apart from these material properties, increase the psychic powers of an individual by their curative powers.  Astral gems also have the power to ward off the ill-effects of planets and worn in the form of birth stone..\n\n\nThe gem stone / birth stone should be set in the right metal and with the right weight.  It should be worn on the correct finger of the working hand.Each gem, with its constant source of specific rays,gives rise to constructive vibrations that have therapeutic powers. Hence wearing your appropriate birth stone will always give you luck and prosperity.
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It is possible to grow crystals that are naturally red.  You grow them from potassium ferricyanide (not the same as cyanide).  \n\nThese links have more information about red crystals.  I hope this helps.
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This past summer the wife and I took a trip to NC. Spruce Pine to be precise. We went "Rock Hounding" or "Gem Mining" at place called  Gem Mountain.\n\nhttp://www.gemmountain.com/aquamarine.htm\n\nWhile at Gem Mountain we purchased one bucket of minerals and mined at their Aquamarine mine near by.\n\nWe found some nice specimens, but one in particular stuck a nerve, The image of this Aquamarine is posted at my site, Take a look:\n\nhttp://my.opera.com/TheMineralExchange/albums/showpic.dml?album=157930&picture=2347315\n\nOk.. so after viewing the image, Aquamarine's stats are as follows:\nA) : Green-blue\nB) : White\nC) : 2.63-2.91\nD) : 7 1/2-8\nE) : Hexagonal\nF) : Imperfect\nG) : Conchoidal, Uneven, Brittle.\n\nHey Teacher?. did I pass?
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Ruby is not a mineral in its own right, it is a variety of the mineral CORUNDUM. Ruby is the name given to corundum (aluminum oxide) which is coloured red by having small amounts of chromium as an impurity (blue sapphire is corundum with iron and titanium). Ruby is found in many areas around the world but only in small ammounts. Ruby good enough to cut into gemstones is VERY rare. So rare in fact that the price the prices per carat of fine rubies are the highest of all gemstones including diamonds.
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No, limestone becomes marble under enough heat and pressure. \n\nShale is formed from clay.\n\nBy the way, almost NO limestone is formed from chemical precipitates from seawater. It is formed from the remains and shells of living organisms, like clams, oysters, coral, algae, and bacteria.
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Wow, this would take a book to explain in detail!  I'll try to explain as briefly as I can. \n\nMost minerals are crystals*.  \n\nCrystals are basically formed by an arrangement of atoms in a pattern that repeats itself in 3D.  They start as a small cluster of atoms which grows into a recognisable crystal as more atoms are attracted by the electrical forces of those already in the crystal structure.  \n\nCrystals are formed mainly from molten solids (such as in molten magma) and solution (in water) and less often, from vapors (i.e. gases).  \n\n* Some minerals are not crystalline.  E.g. Opal, Obsidian.  These exhibit an amorphous character, meaning they have no crystal form or structure.  \n\nHope that helps a little!
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the typical color is a beautiful,hue known,in fact,as emerald  green and its due to traces of chromium in the crystal structure\nbut they can be light or dark green,bright green or leaf green.The\nvitreous luster its not outstanding,and is strongest in medium-light stones with few inclusions.ALL emerald contain inclusions,\nalthough in THE BEST quality stones,these are very faint and not visible to the naked eye.They show up under a 10x,20x or 40x lens.\nthe most common shape for gems is the STEP or TRAP CUT,which is also known as the EMERALD CUT.\nBy the way Colombia is the number one source of high quality emeralds (Chivor and Muzo mines)the biggest and most beautiful emeralds come from this mines.\n about the value ,stones of fine color,weighing more than 2 carats\nare among the most highly valued gemstones,and their price \nmay equal or exceed that of diamonds.less ideally colored varieties--TOO DARK OR TOO PALE--are worth quite a lot less;\nand if they are slightly turbid as well,the value is reduced even further
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There are many crystal shapes.  The standard is an elongated six sided coming to a pyramid like point at the top.  Some, however, are double terminated (have points at both ends). Some (such as garnets) have six sides, but are flat on top and almost roundish looking.  Others, such a mica, are in flat layers.  Others still, can come in cubes (such as pyrite)  Some crystals have no particular shape at all (globular)(such as malachite).  So there is no one particular crystal shape.
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Glass is a manmade material that is made of melted sand that has been shaped and molded. Crystals are naturally occouring mineral formations caused by extreme pressure and heat from rock layers when the crystals are formed. They are similar (in that they can both be caused by heat), but one is natural and one is manmade. Crystals also have much more magical energy.
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Agate & Quartz are both composed of SiO2 or silicon dioxide.\n\nAgate is a cryptocrystalline version of quartz.(very small, as not to be seen with the naked eye, crystals) \n\nAgate is formed in sedimentary deposits from dissolved quartz that is redeposited. This is usually near the surface where there is lower pressure & temperatures.\n\nMany times agate is found as geodes. These are really cool. Sometimes they fill in completely w/ layers of silica. Other minerals may be present as to make color bands. Other times the geode will not fill completely in before crystals start forming. WOW! Love these!\n\nSometimes from the process mentioned above, cryptocrystalline silica will seep into bones & remnants of tree trunks. Ever seen petrified wood? OF course this is not the only mineral that will do this in wood & bones.\n\nOpals are also a variety of quartz. It contains minute amounts of water in its structure. The only difference here is that opals are amorphous meaning that there are no crystals.\n\nSilicon Dioxide is the most abundant mineral in the earth's crust. It is found everywhere and in all kinds of forms.\n\n:)
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“Making your own Crystals”\n\nA crystal is a special kind of rock. Different crystals have different beautiful shapes and colors. \n\nWhat you'll need\n\n Your magnifying glass \n Table salt \n Epsom salt \n Honey jar \n Measuring cups and spoons \n Paper cut into circles \n Scissors \n Pencil \n String \n 1 3/4 cups of sugar \n 2 or 3 paper clips \n A glass jar or drinking glass \n Your science journal\n\nWhat to do\n\n \n\n1. Use your magnifying glass to look for crystals. Inspect: \n1. The table salt and Epsom salt; \n\nThe honey jar (particularly if it has been open for awhile) and \n\nThe walls of the freezer (if it's not the frost-free kind). \n\n1. Draw pictures of what you see in your science journal. \n1. Do all of the crystals look the same? \n1. If not, how are they different? \n1. Try dissolving salt crystals and forming new ones: \n1. Dissolve 1 teaspoon of salt in 1 cup of water\n1. Grown-up alert! \n\nHeat the mixture over a low flame to evaporate the water. \n\nWhat's left? \n\nWhat shape are these crystals? \n\n1. Snowflakes are made of ice crystals and are beautiful, but they are hard to see clearly. You can make paper snowflakes. \n1. Take a circle of paper (use thin paper) and fold it in half. Then fan fold it. \nMake cuts along all the edges. Unfold them. \n1. Grow rock candy crystals from dissolved sugar. \n\nGrown-up alert! \n\nPour a cup of boiling water into a dish and add 1 3/4 cups of sugar. Stir until the sugar is completely dissolved. Prepare a jar or glass as shown. \n\n\n\nWash the paper clips and use clean string. When the sugar water is cool, pour it into the jar and put it where no one will move it. Hang the paperclips in the water and put the pencil on top of the jar. \n\nSome crystals may form in a few hours. Some may grow to be half an inch on each side. To save them, take them out of the water and keep them dry. But they may disappear--they are good to eat. \n\nWhen certain liquids and gases cool and lose water, crystals are formed. Crystals are made up of molecules that fit neatly together in an orderly package. All crystals of the same material have the same shape, regardless of the size.
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Pure quartz is clear and translucent, but natural quartz is typically tainted with impurities, and it takes on the color of those. Here are some examples:\n\n# Amethyst's color is due to an iron (ferric, Fe+3) impurity-induced color center\n# Citrine's color is due to an iron (ferrous, Fe+2) impurity-induced color center\n# Milky quartz's color is due to microscopic air, carbon dioxide, or water inclusions\n# Rose quartz's (crystalline) color is due to aluminum and phosphorus impurities - massive rose quartz's color is due to microscopic and, as yet, unidentified dumortierite-like fibers\n# Smoky quartz's color is due to an aluminum impurity-induced color center aided by natural irradiation
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You'll have to consult a geology textbook to get a good answer on this.\n\nBasic answer: The shapes that the molecules take when they come together to form minerals, form in regular patterns.  That is, they align very regularly next to the last molecule.  The angles that these bond also form the angles at which the minerals form and cleve.
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Jewelry is the only place I know amethyst to be used. Amethyst is a purple quartz. Sometimes it is superheated to produce yellow quartz--citrine.\n\nIn addition to its color being beautiful, amethyst occurs often naturally in large pieces that can be faceted for large, showy gemstones that can be bought at relatively reasonable prices.