How are mineral stones formed?

A stone is a naturally occurring solid formation of one or more minerals. There are thousands of types of stone that have been quarried over the centuries. Quarries are located all over the world. Most natural stone comes from Italy, Spain, Turkey, USA, Mexico, China, Taiwan, India, Greece, Canada, France and Brazil. The minerals in the stone came from the same liquid and gaseous minerals that formed the earth. The Earth developed as a massive body of gas and liquid minerals that slowly cooled and condensed into a solid core. Under pressure, the Earth’s crust began to form, and heavy minerals were forced into the Earth’s core, where they became trapped. As the crust became thicker, it contracted around the inner core, creating intense pressure and heat within the Earth. Crystals and other solid forms began to grow from the mineral vapors that were released. As the Earth’s crust began to expand and collapse, heat and pressure pushed solid minerals to the Earth’s surface, which formed colossal layers of rock. Some of these beds took up to a hundred million years to form. Many of the beds are now used as quarries for stone. Most of these minerals can be identified by their color, hardness, and crystal formation. Crystals come in different shapes and sizes. The wide range of these minerals is often difficult to identify. Many stones are very similar to each other; However, they are all very different. It is essential to know the exact type of stone that needs to be preserved. The stone is natural and may have adverse reactions to some cleaning chemicals and procedures. Most rocks are also naturally alkali, as well as dirt and soil; Consequently, stone and dirt are attracted to each other, which often makes cleaning very difficult. This makes choosing the right cleaning procedures and chemicals for the stone very difficult. The known types of stones in use today are identified in four categories: SEDIMENT, METAMORPHIC, STONE and MAN. PRIMARY stone came from organic elements such as glaciers, rivers, wind, oceans and plants. Tiny sedimentary fragments broke off from these elements and accumulated into rocks. They were connected through millions of years of heat and pressure. SAND STONE: Very durable formation of quartz grains (sand). Usually formed in light brown or red tones. Categories of the most popular sandstone binders are silica, calcium, clay and iron oxide. Fossil: Considered to be limestone that contains natural fossils such as sea shells and plants. TRAVERTINE: Typically cream or reddish in color. It is formed by the accumulation of calcite from hot springs. It contains many holes that were formed from water flowing through the stone. These holes are often filled with synthetic resins or cement. It requires a lot of maintenance if the holes are not filled. Classified as limestone and marble. SOAPSTONE: A very soft stone made from various talcs. It is a dense mineral that wears well and is often stain resistant. Limestone: Mainly composed of calcite. It doesn’t show much grain or crystalline structure. Has a smooth granular surface. Depends on hardness. Some dense limestones can be polished. Common colors: black, grey, white, yellow or brown. It is more likely to stain than marble. Limestone is known to contain lime from seawater. METAMORPHIC stone comes from the natural transition from one type of stone to another through a mixture of heat, pressure and minerals. The change may be the development of a crystalline formation, a change in texture, or a change in color. Marble is divided into three categories: (Stone World) MARBLE: Recrystallized limestone that formed when limestone softened from heat and pressure and recrystallized into marble where mineral changes occurred. The main consistency is calcium and dolomite. It comes in a variety of colors, usually with strong veining and a lot of grain. Hardness indicators range from 2,5 to 5 on the MH scale. DOLOMITE: if it contains more than 40% magnesium carbonate. MAGNESIUM: if it contains 5 to 40% magnesium carbonate. CALCITE: If it contains less than 5% magnesium carbonate. SLITE: A fine-grained metamorphic stone formed from clay, sedimentary rock shale, and sometimes quartz. Very thin and can break easily. Usually black, gray or green. SERPENTINE: Identified by its markings, which look like the skin of a snake. The most popular colors are green and brown. Hardness indicators range from 2,5 to 4 on the MH scale. Contains serpentine, minerals, contains a lot of magnesium and is of igneous origin. Does not always respond well to diamond recrystallization or polishing. Native stones are mainly formed from volcanic material such as magma. Below the earth’s surface, liquid magma cooled and solidified. Mineral gases and liquids penetrated the stone and created new crystal formations with different colors. GRANITE: Mainly made of quartz (35%), feldspar (45%) and potassium. Usually has darker colors. Contains very little calcite, if any. Provides a heavy crystalline and grainy appearance with mineral grains. It is a very hard material and easier to maintain than marble. However, it is still porous and will stain. There are different types of granite depending on the percentage of quartz, mica and feldspar. Black granite is known as anorthosite. It contains very little quartz and feldspar and has a different composition than true granite. MAN-MADE Stones are obtained from unnatural mixtures such as resin or cement, with the addition of stone chips. AGGLOMERATE or CONGLOMERATE: marble chips embedded in a colored polymer composition. Treasured by all cultures and religions, gemstones have captured the imagination of people for thousands of years. During this time, precious stones were credited with protective properties, healing, wisdom, even invisibility and life. But where do gemstones come from? Most gemstones are composed of crystalline forms of various minerals (with the exception of non-mineral, organic stones such as pearls, coral and amber). Minerals are formed through natural processes that combine chemicals, heat and/or pressure. The concentration of chemicals determines the structure and color of the crystals. The temperature and pressure at which crystals form affect their size and shape. Most mineral crystals are tiny, but some grow large and thin enough to be cut into gemstones. These gems are the crown of the mineral world. Although we don’t think about it, minerals play an important role in our daily lives. They form rocks in the earth’s crust, fill our homes, highways, and are essential components of all our technology. Mineral crystals are formed during one of three rock formation processes and therefore fall into one of three categories: igneous rocks, metamorphic rocks, and sedimentary rocks. Igneous rocks Deep within the earth, molten rock called magma bubbles. Magma can be produced from the mantle or from the melting of rocks due to increased temperature and/or pressure, or changes in chemical composition. These changes can occur as a result of tectonic processes in the bowels of the Earth. The mantle is fluid and mobile because heat from the core rises to the surface. This creates currents in the mantle that move in a circle. When magma rises from the mantle deep within the Earth, intense pressure is created that pushes some of the liquid rock to the surface. Once cooled, it can be classified as an igneous rock. There are two types of igneous rocks: intrusive and extrusive. Intrusive igneous rocks never reach the surface and are exposed only by weathering or tectonic movement. They are often dome/bowl shaped or pipe-like. Dome- and bowl-shaped formations occur because magma is pushed through the rock, much like lava in lava lamps moves toward the top of the lamp, reaching an area of ​​resistance where it then accumulates. Pipe-shaped igneous formations occur when magma moves through weak spots in the crust without reaching the surface or an area of ​​rock that it cannot easily pass through. It then either stops and cools, or accumulates to form one of the dome- or bowl-shaped formations. When igneous formations cool, crystals form. Intrusive rocks often have a coarse-grained structure because they cool slowly, allowing the crystals to grow in size. Extrusive igneous rocks come to the surface, sometimes quite violently. Once on the surface, they cool quickly. This often creates pockets of trapped gas, or cavities, called vesicles in the rock. Examples of gemstones formed in igneous rocks are tourmaline, aquamarine, topaz, kunzite, and feldspars such as sunstone and amazonite. Many other gemstones can be found in igneous rocks, but they are not a direct result of the formation of igneous rocks. They are called secondary deposits because they form after the primary deposit. Many of them are formed as a result of hydrothermal processes, when very hot water enters the cavities of existing rocks. Water is able to transport chemicals into cavities or vesicles, which then form minerals.

Sun Stone

Examples of gemstones that occur as secondary deposits in igneous rocks are amethyst, larimar, and fire opal.

fire opal

Metamorphic rocks Metamorphic rocks form when existing rocks are subjected to intense increases in pressure and/or temperature, causing changes in the mineralogical composition, texture and structure of the rocks. Metamorphic rocks often go through a process called recrystallization. Recrystallization occurs when temperature and pressure become high enough to break the atomic bonds in rock bodies and change their structure without changing the underlying composition. It’s similar to how you mix ingredients to make a cake. The eggs, milk and filling look different when they are not mixed in a bowl, but after mixing and cooking in the oven, the composition of the cake did not change, but the state of its ingredients did. Metamorphic rocks can form through regional or contact metamorphic processes. Regional metamorphic rocks often form deep within the earth due to extreme temperatures near the mantle and intense pressure from the overlying rocks. They can also form as a result of large-scale tectonic movements, such as the formation of mountains. Contact metamorphism occurs as a result of contact with molten rock. Between the parent rock and the igneous rock is a metamorphosed zone that can exhibit all degrees of metamorphism. Metamorphic rocks near an igneous intrusion may have an altered chemical composition due to the ingress of hydrothermal fluids that were released from the igneous rock as it cooled. These hydrothermal fluids can replace or partially replace existing chemicals in the metamorphic rock. This is called metasomatism. The further away from the heat source, the degree of metamorphism decreases. Examples of metamorphic gemstones are tanzanite, garnet, ruby, sapphire, emerald, spinel and kyanite. Sedimentary rocks Sedimentary rocks are formed as a result of processes occurring on the Earth’s surface. They may consist of other sedimentary rocks, igneous rocks, and metamorphic rocks. Some sedimentary rocks are chemically precipitated from solution. Others are biochemical or organic in origin and consist of calcium carbonate formed from the shells of extinct organisms or from the decay of organic tissues of plants and animals. Most sedimentary rocks are composed of fragments of igneous rocks that are cemented together. When rocks of all kinds come to the surface, they undergo an erosion process called weathering. Weathering is the physical destruction of rock by physical forces such as wind, rushing water, or expanding ice. These rock fragments are often washed into rivers and/or the ocean. Over time, layers of rock debris, dirt, and other organic and inorganic elements are compacted into solid rock. Examples of sedimentary rocks are limestone, shale and sandstone. Examples of gemstones of sedimentary origin are aragonite and calcite. Surprisingly, most gemstones are found in sediments after they have been weathered from their original rock. Found in river sediments and known as alluvial sediments, these gemstones include gemstones such as diamond, spinel, sapphire and ruby. In each of the above cases, the atoms form complex but ordered structures called crystals. The structure and chemical composition of the mineral together form the properties of the crystal, such as shape, hardness, cleavage, refractive index and others. This is why the origin of gemstones is so important. How they are formed and under what environmental factors greatly influences their physical and chemical properties. This gives us yet another reason to treasure our incredible gemstones.