What is the difference between red agate and carnelian?

Carnelian, a variety of chalcedony, is a cryptocrystalline variety of silicon dioxide. The name of the stone comes from the Greek word sardolith, which means “stone from Sardis,” the capital of ancient Lydia. Sarders are usually called brown-red, chestnut carnelians. The name of orange-red carnelian – carnelian – goes back to the Latin carnis – “flesh” and indicates the warm, “flesh” color of the stone that iron compounds give it. Orange-yellow and yellow carnelians are called lincuria (Greek lynx – “lynx”). Carnelians are figuratively called “stones of the sun.” L
Magical and healing propertiesThe ancient Egyptians considered carnelian the stone of the goddess Isis (the mother of all gods). They believed that carnelian could protect from evil spells and dangers, both in this world and beyond. It is no coincidence that many items decorated with carnelians were found in the tomb of the pharaoh. In the Middle Ages, Arabs and Persians wore carnelian stones in the form of amulets with prayers from the Koran carved on them and believed that such amulets protected them from envy and the “evil eye”.
Carnelians have long served as symbols of true love. According to ancient beliefs, carnelians protect against human ill will, the intrigues of enemies and evil spells. As a talisman, jewelry with carnelians can be worn to soften anger and lift spirits. It has long been believed that carnelians contribute to wealth and give the owner strength, including creative ones. Agates are varieties of fine-fibered chalcedony, which are characterized by layered coloring. These layers can be concentric or linear. They seem to repeat the outlines of underground voids – geodes, in which agates often form.
The name of these amazing “striped” stones comes from the ancient name of the Achates River in Sicily, where agates were mined in ancient times. According to another version, the word “agate” comes from the Greek ahates – “happy”. The color of agates varies from milky white, yellowish and greenish to almost black. If layers of yellow, red, brown, black or another color alternate with white layers, then this type of agate may have its own name. For example, the most beautiful are the so-called “eye” or “spectacled” agates with concentric layers located around a central point. Such stones were sometimes called “owl eyes”. In some agates, a zone just 1 cm wide can contain up to 7000 different layers. In the countries of the ancient East, the so-called “moss” agates with patterns similar to lush forest thickets were especially valued. Agates with tree-like stains and inclusions are called “dendritic” or “dendritic” stones (Greek dendron – “tree”). Depending on the color options, “cloud”, “rainbow” and “flame” agates are distinguished. The color of agates is varied, and essentially it is individual for each stone.
Agate deposits are associated with volcanic rocks (lavas, tuffs) and are found in almost all countries of the world. The most beautiful stones are mined in Uruguay, Brazil, India, Arabia and Sicily. In Russia, agates have long been mined in the Urals.
Magical and healing properties
In ancient Rome, agates were the stones of the fertility goddess Pomona, who was the patroness of the harvest and gardening. In ancient times, it was believed that agate evokes God’s mercy. It gives the owner courage and longevity. In Europe, agate was a symbol of health, prosperity and longevity, in India – prosperity. People believe that agate jewelry makes its owner pleasant to talk to and eloquent, and also protects him from the machinations of enemies. It is believed that white and yellow agates enhance the good nature of a person, soften his character, and promote inner peace and confidence. Black agate is considered a male talisman that protects the owner from evil forces. Other answers
You can find out more about stones on the Internet. Almost nothing in terms of chemical composition is the same. Only Agate contains inclusions that create patterns in the form of rings. Both are chalcedony. True, agates come in different colors. Carnelian is the name given to chalcedony of a certain color (such a pale red color). Carnelian-colored agate is also called carnelian. To a group under a common name “cornelian” combined are translucent, essentially chalcedony varieties of quartz of red, orange and yellow colors with a characteristic brownish tint. Carnelian is a tough, durable stone. However, sometimes, as a result of intermittent growth of the chalcedony aggregate, the boundaries of the zones are weakened, and shell-like separation appears along them. Genetically, carnelian is a silica mineral aggregate formed during post-volcanic hydrothermal activity. When exposed to heat or X-ray irradiation, the iron contained in chalcedony transforms from the oxide form to the oxide form, which leads to the appearance or intensification of an existing color. The textures of carnelians are similar to those of agates. The main factor determining the decorative qualities of carnelians is color. The most prized are the brightly colored red varieties. In all varieties of carnelian, there is a clear pattern in the manifestation of another of its main properties – translucency: the thicker (darker) the color, the lower the degree of translucency of the stone. Exceptions are individual non-translucent (or weakly translucent) surface zones—“crusts” (in sardonyx—single zones of milky chalcedony, quartz, or white porcelain opal). Chalcedony actually called solid, homogeneous translucent stones, grayish or bluish-gray. Chalcedony has been known since ancient times. The name of the stone comes from the ancient city of Chalcedon, which was a center for the processing and sale of this stone. Peculiar chalcedony from a number of deposits in the Dzhambul region of Kazakhstan, colored pinkish, yellowish and reddish in texture and formation, stand out in an independent group of jewelry and ornamental stones, forming lenses and vein-shaped and confined to horizons of limestone cherts, mudstones and siltstones, these chalcedony genesis are hydrogenous low-temperature formations. Among them, brown, red-cherry, lilac, pink, gray, pink and brown varieties are often found, and different color combinations can sometimes be observed in one ore. The color distribution is uniform, most often unclear. Sometimes spots of a bluish-gray, milky dirty green color are observed. The stones are translucent or transparent in thin chips and plates 1-2 cm. Hardness 6,5-7. The fracture is conchoidal, the shine is in the fracture. The combination of bright beautiful coloring, translucency and polishability determines the high decorative qualities of chalcedony. There is a variety of chalcedony called opalom. In addition to silicon dioxide (Si02), its composition includes a certain amount of water (3-9%). According to recent studies, opal aggregates are composed of tiny silica globules and spherulites measuring 4000-1500 A in size. The gaps in the aggregates are partly empty, and partly filled with silica or water colored with iron oxide. Light reflected and scattered by the surfaces of the pores creates an iridescence of opals, often called “fire play”. Opal probably got its name from the Latin word “opalus” – striking the eyesight, enchanting the eye. Opal has a hardness of about 5-5.5, sp. weight 1.9–2.3, conchoidal fracture, Opals have gained fame as beautiful ornamental stones thanks to the special enchanting beauty hidden in their ability to subtly change color. Among noble opals, fire varieties are especially valued, where the “opal play” is combined with the brick-red color of the stone. Noble and fire opals are valued significantly higher than turquoise, carnelian, agate, amber and many other gems. In addition to noble opal, jewelers also value milky white varieties similar to ivory. They are known under the name of the already mentioned cacholong, which represents a transition from opal to anhydrous chalcedony. Unfortunately, noble and fire opal have a lot of invisible microcracks that occur due to dehydration of the opal gel as it hardens. The characteristic features of the fine structure of opal, which create its fiery play, are at the same time the reason for its instability in bright sunlight. When exposed to the sun, the opal begins to become cloudy and fade. When worn for a long time in jewelry, it has a specific aging property. Therefore, there is probably a belief that opal is a stone that brings misfortune. When processing opal, it should be borne in mind that overheating the sample can lead to a loss of transparency and play of colors, as well as to an increase in its fragility during cutting, grinding and polishing. Recently, opal has come back into fashion in jewelry. It is especially beautiful in a hemispherical shape, in so-called cabochons in a gold frame, which emphasizes the play of the stone. Agate– a concentric, thin-layered stone, each layer of which is composed of differently colored chalcedony with an arrangement of fibers perpendicular to the layer. Ordinary agate has alternating blue-gray translucent layers with white, almost opaque layers. The following are distinguished by color: cornelian – the most valuable variety of all the stones of the chalcedony group, with the exception, perhaps, of chrysoprase – a more or less homogeneous chalcedony, colored red or brown-red; carnelian – sometimes this term is considered a synonym for carnelian, but more often it is considered as a variety whose red color is brighter and purer than that of carnelian; The color of carnelian can be improved by heating the blanks; It is recommended to wrap it with asbestos cord as a container. In this case, the flame should be kept low for approximately 1 hour to remove all moisture, then the flame should be increased to medium strength until the entire stone is hot. Cooling should be long enough. sarder (sard) – usually brown or red-brown chalcedony, highly translucent; onyx – agate in which brown or dark brown, almost black, layers alternate with white and yellow. In ancient times it was the most popular stone. The more varied, contrasting and thinner the layers, the more valuable the stone. Cameos are usually carved on onyx, and the artist uses not only the relief, but also the coloring of the layers. When making crafts, the direction in which the onyx nodule is cut is especially important—it is necessary to emphasize the layering and pattern of the onyx; sardonyx – agate with alternating red and red-brown layers. Extremely rare in nature. It should be kept in mind that many sardonyx products, especially those made in foreign countries, are artificially colored. In later times, new names appeared. Moss agate – often white or bluish chalcedony, in which tree-like or grass-like inclusions (dendrites) are distributed throughout the entire thickness of the stone. These inclusions can be black (manganese oxides), brown, brown-red (iron oxides) or green (chlorite or celadonite ingrowths). The most valuable is moss agate with green moss growths. A peculiar pattern of agate, where more or less even layers are broken up by parallel lines and shifted, reminiscent of a fortress, towers, etc., is called bastion agate. sapphirine – bluish chalcedony with a clear blue tint, wax agate – a bright yellow, homogeneous, wax-like, highly translucent stone. Caholong – bright white chalcedony, reminiscent of ivory – an opaque porcelain-like milky white stone, sometimes with a grayish tint. This name was also assigned to the milky-white aggregate of chalcedony with an admixture of opal, which is externally indistinguishable from cacholong opal. The white color of cacholong is in most cases associated with magnesite inclusions. Hardness of cacholong-chalcedony and cacholong-opal 5-5,5. The fracture is smooth to flat-conchoidal (in cacholong-opal it is conchoidal); sharp cutting edges. In thin (up to 1 mm) chips the stone sometimes shows through. The luster is waxy (cacholong-opal has a glassy luster). Cacholong-chalcedony is a mechanically strong, tough stone; Cacholong opal is fragile. Cacholong opal is formed in surface or near-surface conditions as a result of biochemical processes or precipitation processes from solutions at ordinary temperatures and pressures. Cacholong is found mainly in the form of nodules, as well as short lenses and veins ranging from 3 to 40 cm in length. The shape of the nodules is isometric and irregular, often somewhat flattened or elongated. The surface of the bodies is uneven (lumpy, kidney-shaped or ribbed) with a clearly defined polygonal system of desiccation cracks, sometimes ferruginous; The depth of penetration of cracks into the stone usually does not exceed 5 mm. B In the peripheral part of the nodules, a white or gray siliceous porcelain-like crust with a thickness of several millimeters to 1 cm is often observed. The border between the porcelain-like crust and the main mass of the nodule is sometimes shaded by a thin (up to 2 mm) translucent light-smoky zone, roughly following the contours of the nodule. L.A. Solovyova notes the gradual compaction of the stone from the periphery of the nodule to the center. The bulk of the stone is milky white or grayish-white, non-translucent, the structure is cryptocrystalline, the texture is uniform. The most highly prized are pure white porcelain-like varieties.. In some cases, chalcedony includes green siliceous rocks, sometimes it is fine-crystalline quartz, opal or jasper. Plasma – a dirty green, apple green, translucent or completely opaque breed that takes polish well. Close to plasma are chrysoprase – translucent bright green chalcedony (fine-grained quartz, colored with an admixture of nickel silicates) and heliotrope (bloodstone) – green jasper or plasma with small bright red spots. Green varieties of chalcedony are valued more than other agates and chalcedony. The cost of heliotropes is especially high. At the end of the last century and at the beginning of this one, several more varieties of chalcedony and agate were identified based on their optical properties. This includes primarily quartzine – an aggregate of fibers that are similar in appearance to chalcedony, but have a different optical orientation. It is extremely rare and does not stand out as an ornamental stone. Lucatite – sinter varieties similar to chalcedony or agate, consisting of cristobalite fibers, but differing from quartz in density and optical properties. If an agate is entirely composed of lusatite, then it is impossible to distinguish it from other agates, but if there are separate lusatite layers in an ordinary agate, then they are sharply distinguished by their low light refraction. When the layers of agate are so thin that their thickness is commensurate with the wavelength of light, a play of color appears in the stone, and then it is called iridescent Agatha . Such agate is very rare and is almost never found in products; it is very difficult to process, since the iridescent agate insert must be oriented very strictly, otherwise its play will not be visible. Decorative flints, due to the relative rarity of brightly colored “patterned” varieties, did not immediately enter human use as an ornamental stone, in contrast to the widely developed, long-used technical stones. Decorative flints are monolithic thin — and cryptogranular siliceous formations (concretionary, lamellar, cylindrical and shaped), plain or variegated. Their hardness is 6-7, the fracture is rough, conchoidal to splintered. Flints are well processed, ground and polished, and are mostly suitable for the production of small stone-cutting products. The decorative effect of the stone is determined by the color and pattern. Brightly colored flints with fine designs are sometimes used as insets in inexpensive jewelry. Flint is also chalcedony, but unlike agate, it lacks any structure. It is formed among limestones, forming irregular sections – nodules or concretions. Flint is often painted in gray-blue tones; as an ornamental stone it is of no interest. There are flints of different colors with quite beautiful patterns. Flint is 90-95% chalcedony, but it also contains quartz, opal, clay minerals, sand, and pigments, so it is more correct to call it chalcedony rock. Flint has a conchoidal fracture and is colored gray, yellowish and black. Flint with a horny color is usually called hornfels. Particularly beautiful are the patterned striped flints, ranging from white with black stripes to yellow, pink and blue. Flint polishes very well, but is difficult to process due to its high viscosity and hardness. Flint got its name from the Greek word “kremos” – stone, cliff. Flint is extremely common and is found throughout sedimentary rocks. Even in prehistoric times, the first stone tools were made from flint and hornfels, intended for hunting, labor and making fire, tips for arrows and spears, axes, and scrapers. flint, etc. The fact that under the influence of fire flint breaks up into very strong and sharp fragments apparently played a decisive role in its development by primitive man. Based on the study of primitive man’s flint products, many data known to us about primitive society were obtained. The beauty of flint is not immediately apparent. Flint nodules are usually covered with a white shell, and the patterned-striped beauty of the stone is revealed only when cut after polishing it. Beautifully painted patterned flints are successfully used to create small decorative and artistic stone-cutting items such as boxes, stands and for jewelry inserts. Flint has high technical qualities and, like jasper, finds valuable application in technology. In most cases, such flint is cracked, but individual dense nodules take polish well, and the products made from them are quite elegant. Flint can often be found in river pebbles and on beaches. In flint nodules, there are often voids in the center or along the edges, in which agate-like leaks or quartz crystals stand out. Amethyst crystals were sometimes found in cavities in flints near Moscow. There is another specific type of agate – Ural, it is called overflow. Among the more famous Ural jewelry stones, a modest but rightfully special place is occupied by the colored stone, discovered back in 1791 by a participant in one of the expeditions to study the nature of Russia, court adviser A. Razderishin. This happened on the eastern slope of the Middle Urals near the old village of Shaitanki, hence the name of the mineral – Shaitan overflow. This mineral is attractive with its beautiful wavy pattern and delicate tones of variable color – milky white, sometimes yellowish, smoky or greenish with picturesquely distributed light brown, and sometimes reddish stains and spots. Defined by A. Razderishin as chalcedony, Shaitan overflow was found in the form of blocks near the very surface of the earth. Its peculiarity is the rather spectacular colors of thin layers: white and orange-pink. In addition, this agate stands out in a thin crack among crystalline rocks, sometimes filling this crack entirely, and sometimes only growing on its walls. The overflowing crack extends over a fairly long distance. The nature of the overflow is not yet entirely clear. Thanks to the authority of A.E. Fersman, who assigned a place to iridescence either among banded chalcedony – agates, or together with chalcedony in the category of cutting stones, the identification of this mineral with chalcedony was not disputed by anyone. However, a detailed study of the ontogeny of the mineral using modern equipment shows that the Shaitan overflow is not chalcedony at all. And the geological environment in which the overflow was discovered is completely unsuitable for the formation of a fibrous variety of silica – chalcedony. Excretions of agate and chalcedony are usually associated with hydrothermal hot solutions, which are a product of volcanic activity, and under conditions of low pressure near the surface. An increase in pressure leads to the formation of quartz instead of chalcedony or agate. The area of the overflow deposits is composed of deep rocks, and there are no volcanic rocks here. How, then, did the overflow form? The Shaitan overflow is an interlayering of microcrystalline quartz with dickite, thin quartz crusts and the already mentioned first generation quartz. The name “chalcedony” is completely untrue. Interestingly, overflow does not lend itself to artificial coloring, which is used to change the color of chalcedony. This is explained by the fact that the overflow does not have the porosity due to which the pigment could be fixed in the stone. As a colored ornamental stone that takes polish well, Shaitan overflow is currently used in the stone-cutting and jewelry industries. It is used to make beads, necklaces, round and oval cabochons. Among the antique items, one can note an iridescent ashtray, framed in silver and decorated with garnets, made by the Peterhof Lapidary Factory. This ashtray is located in the Pavlovsk Palace Museum. In other museums, and in particular in the Hermitage, there are mosaic items with fragments of stones similar to Shaitan’s overflow, but most likely they come from foreign deposits.