* They are stones based on silica, containing crystallized minerals, and gemstones vary according to the variety of minerals that are included in their composition, and these stones are formed in the ground at different depths.  Man has known precious stones from eternity, and he used them to make spearheads due to their hardness, and also to make jewelry and amulets due to the beauty of their colors and their hardness. The stone was called precious because of its rarity.

 * Due to the difficulty of extracting, polishing and shaping it, and to this day the processes of extracting and manufacturing it in its final form are expensive, and this made the prices of precious stones high and unaffordable to many people.

 * The stones available in the market are divided into three types:

 1- The original stones, natural stones, or precious stones:

 They are stones that were formed in the earth's layers over thousands of years after their elements were subjected to high pressure and heat in the earth's layers.  Diamonds are one of the most common and the highest price, and it is also one of the hardest and hardest, as it is difficult to scratch, and in general all precious stones are expensive.

 * It is considered a real treasure that companies and countries compete in exploring and extracting from the ground, but one of the disadvantages of the extraction of these stones is that they destroy the environment, by transforming large areas that may be agricultural or environmental in which wild animals live, and the extraction processes transform them into mines that are not suitable for living, planted with excavators  Crushers and excavators,

 * In addition to employing many workers to work for low wages compared to the return and great benefit from it, which is attributed to a small number of beneficiaries.  It is important to know that some precious stones after their extraction are treated in the laboratory, and this process is very important to refine the stone and show the hidden luster and luster of it, for example, tanzanite stone is brown when extracted from the layers of the earth, and it is treated with heat in the laboratory to show its brilliant color that is between the two indigo colors  And blue.  And this stone is no exception.

 2- Artificial stone: It is a stone that is prepared in the laboratory, with the same materials that the original stone is made of, after trying to simulate the conditions in which the original stone is produced from heat and pressure, but with less standard time, among its advantages:

 * This type of stone is less expensive.  In terms of quality it is excellent compared to natural stone.  It is difficult to distinguish it from the original stone except with the use of expert tools. For example, the refractive index of the stone is examined to distinguish between natural stone and artificial stone.  It beats the original stone in terms of fewer impurities.  Colors can be varied;  Where those who produce these stones have the ability to dye them in a variety of colors that imitate the more rare species in nature, such as the yellow diamond.

 * This type is like renewable energy that does not run out, while natural stones are more rare in nature and need thousands of years to be renewed.  Traditional stone: This type of stone is also manufactured in the laboratory to mimic the original stone, but the components of this type of elements differ, and the manufacturing stages that the stone goes through are different. This type can be seen at first glance as a natural and expensive gemstone, but upon checking it is  He can see the impurities and defects of the stone and the lack of clarity of its color and luster, but what distinguishes this stone is its low price compared to natural stone, so the piece inlaid with it can be used on a daily basis.

 * The comparison between natural stone and traditional stone is very easy, and it does not require any tools, just an eye test with a little practice, by examining the purity of the stone can be seen;  The natural stone is usually bright, clear, and the traditional stone is less transparent and has dark spots, and it is seen from every angle in a different color compared to the natural stone, whose luster remains at one of different points and angles.

 * As for the comparison between natural stone and artificial stone, it is more difficult, and it is not possible to distinguish between the two stones by looking

 1- Wiping the surface: If the surface is rough or sandy and easy to break and fragment, then this is evidence that it is not a precious stone.

 2- Examination of the color of the stone: detailed tables are used in this examination and developed to accurately describe the colors of the stones, and the process is divided into three stages: First: Examining the general color of the stone, and comparing it to the color in the tables.  The second: Determining the intensity of the color, i.e. is the color dark, medium or light in color?

 * The third: saturation and concentration of color: This examination helps in determining the extent of color concentration, so the stone is described as cold if the color is green, blue, or purple, or the stone is described as having a warm color if its color is red, yellow or orange.  Knocking on the surface, if the surface is capable of being bent or knocked, this is evidence of the presence of more minerals than it is evidence that this stone is precious;  Because the gemstone has the characteristics of hardness, and it is formed by cutting and grinding, not by hammering and pressing.

 3- Examination of the internal structure of stone: Natural stone has the pivotal composition, while artificial stone has its internal composition in the form of curves.  Artificial stone can be plated with gold or platinum.  The artificial stone may show fingerprints or traces of nails that can be monitored.  Imitation stones are lighter than natural stones.

 * Examination using accurate devices, usually a refractive index test device is used, which is available to experts and goldsmiths, and by reading the refractive index of light in the stone, the natural stone is distinguished from the artificial.  The mechanism in this device depends on determining how the path of light changes inside the stone, each gemstone has its own refractive index, so this method can be used in the event that the type of stone is not known to distinguish it, the refractive index is calculated and then return to the tables of refractive index of the precious stones, and it appears  Us type stone,

 * Also, by knowing the refractive index, it is possible to determine whether the stone is natural or artificial.  The mechanism of using the device is simple: a drop of the examination liquid is placed on the tray of the device, and a stone is placed on it.  Looking through the lens without zooming in to see where the bubble appears, and from the bottom of the bubble a reading is taken.  A second reading is taken, but this time after using the magnifier and determining the accuracy of the first reading;  Some transparent or translucent gemstones have two or more refractive factors.

 A polarizing telescope is used to examine them.  Place the stone inside the device.  Look through the lens and turn it until the area around the stone appears darker or darker.  Rotate the lens up to 360 degrees while observing the color change surrounding the stone.  If the area appears dark and remains dark, this indicates that the stone has one refractive index.  If the stone appears light-colored and remains light-colored, then this indicates the presence of more than one refractive index. If the stone appears once dark and once light-colored, this indicates that the stone has two factors of refraction.