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Cushion Cut
A diamond cut is a style or design guide used when shaping a diamond for polishing such as the Brilliant (diamond cut), brilliant cut. Cut refers to shape (Pear cut, pear, oval), and also the symmetry, proportioning and polish of a diamond. The cut of a diamond greatly affects a diamond's brilliance—a poorly-cut diamond is less luminous. In order to best use a diamond gemstone's material properties of diamond, material properties, a number of different diamond cuts have been developed. A diamond cut constitutes a more or less symmetrical arrangement of facets, which together modify the shape and appearance of a diamond crystal. Diamond cutting, Diamond cutters must consider several factors, such as the shape and size of the crystal, when choosing a cut. The practical history of diamond cuts can be traced back to the Middle Ages, while their theoretical basis was not developed until the turn of the 20th century. The earliest diamond cutting techniques were simply to polish the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Diamond Cut History
Diamond is a solid form of the element carbon with its atoms arranged in a crystal structure called diamond cubic. Diamond is tasteless, odourless, strong, brittle solid, colourless in pure form, a poor conductor of electricity, and insoluble in water. Another solid form of carbon known as graphite is the chemically stable form of carbon at room temperature and pressure, but diamond is metastable and converts to it at a negligible rate under those conditions. Diamond has the highest hardness and thermal conductivity of any natural material, properties that are used in major industrial applications such as cutting and polishing tools. Because the arrangement of atoms in diamond is extremely rigid, few types of impurity can contaminate it (two exceptions are boron and nitrogen). Small numbers of lattice defect, defects or impurities (about one per million of lattice atoms) can color a diamond blue (boron), yellow (nitrogen), brown (defects), green (radiation exposure), pur ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ratna Pariksha
Ratna Pariksha is an ancient science on testing gemstones. It was used by the Kosadhyaksha (Superintendent of Treasury) and mentioned in Kautilya's ''Arthashastra'' in order to control the trade of pearl, diamonds and all the other important gems in antiquity. It classifies gemstones into Maha-Ratna and Upa-ratna (lit. Great Gems and Second Class Gems). History Ratna Pariksha is mentioned in Kautilya's ''Arthashastra'' (323-299 B.C.). Vatsayana, the author of the Kamasutra also mentions rupa-ratna-pariksha. The method was also studied by princes in Karnataka Karnataka ( ) is a States and union territories of India, state in the southwestern region of India. It was Unification of Karnataka, formed as Mysore State on 1 November 1956, with the passage of the States Reorganisation Act, 1956, States Re ... during the medieval period. The author of this treatise is very commonly known to be one Buddha Bhatt. There is also mention of another author in the medieval period, Thak ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Flemish People
Flemish people or Flemings ( ) are a Germanic peoples, Germanic ethnic group native to Flanders, Belgium, who speak Flemish Dutch. Flemish people make up the majority of Belgians, at about 60%. ''Flemish'' was historically a geographical term, as all inhabitants of the medieval County of Flanders in modern-day Belgium, France and the Netherlands were referred to as "Flemings" irrespective of their ethnicity or language. The contemporary region of Flanders comprises a part of this historical county, as well as parts of the medieval Duchy of Brabant and the medieval County of Loon, where the modern national identity and Flemish culture, culture gradually formed. History The sense of "Flemish" identity increased significantly after the Belgian Revolution. Prior to this, the term "" in the Dutch language was in first place used for the inhabitants of the former County of Flanders. Flemish, however, had been used since the 14th century to refer to the language and dialects of both ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lodewyk Van Bercken
Lodewyk van Bercken (also known in French as ''Louis de Berquem'') was a mid- to late-15th century Flemish Region, Flemish jeweller and diamond cutter, renowned in the industry for inventing the scaif. The device revolutionized the diamond cutting industry and contributed to increased popularity of diamonds. About Van Bercken was born in Bruges. He is credited with inventing the scaif, a polishing wheel infused with a mixture of olive oil and diamond dust. With the scaif, it became possible to polish all the facets of the diamond symmetrically at angles that best reflected the light. Charles the Bold Charles the Bold, Duke of Burgundy became the Patronage, patron of van Bercken and in the 1470s commissioned him to cut a 137 carat (27.4 g) stone that later became known as the Florentine Diamond. Van Bercken experimented with three diamonds belonging to Charles the Bold. One stone was the Beau Sancy, another became the property of Pope Sixtus V, and the third was given by Char ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sapphire
Sapphire is a precious gemstone, a variety of the mineral corundum, consisting of aluminium oxide () with trace amounts of elements such as iron, titanium, cobalt, lead, chromium, vanadium, magnesium, boron, and silicon. The name ''sapphire'' is derived from the Latin word ', itself from the Greek language, Greek word (), which referred to lapis lazuli. It is typically blue, but natural "fancy" sapphires also occur in yellow, purple, orange, and green colors; "parti sapphires" show two or more colors. Red corundum stones also occur, but are called ruby, rubies rather than sapphires. Pink-colored corundum may be classified either as ruby or sapphire depending on the locale. Commonly, natural sapphires are cut and polished into gemstones and worn in jewellery, jewelry. They also may be created synthetically in laboratories for industrial or decorative purposes in large boule (crystal), crystal boules. Because of the remarkable hardness of sapphires 9 on the Mohs scale of miner ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ruby
Ruby is a pinkish-red-to-blood-red-colored gemstone, a variety of the mineral corundum ( aluminium oxide). Ruby is one of the most popular traditional jewelry gems and is very durable. Other varieties of gem-quality corundum are called sapphires; given that the rest of the corundum species are called as such, rubies are sometimes referred to as "red sapphires". Ruby is one of the traditional cardinal gems, alongside amethyst, sapphire, emerald, and diamond. The word ''ruby'' comes from ''ruber'', Latin for red. The color of a ruby is due to the presence of chromium. Some gemstones that are popularly or historically called rubies, such as the Black Prince's Ruby in the British Imperial State Crown, are actually spinels. These were once known as "Balas rubies". The quality of a ruby is determined by its color, cut, and clarity, which, along with carat weight, affect its value. The brightest and most valuable shade of red, called blood-red or pigeon blood, commands a lar ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Adamantine Lustre
Lustre (Commonwealth English) or luster (American English; see spelling differences) is the way light interacts with the surface of a crystal, rock, or mineral. The word traces its origins back to the Latin ''lux'', meaning "light", and generally implies radiance, gloss, or brilliance. A range of terms are used to describe lustre, such as ''earthy'', ''metallic'', ''greasy'', and ''silky''. Similarly, the term ''vitreous'' (derived from the Latin for glass, ''vitrum'') refers to a glassy lustre. A list of these terms is given below. Lustre varies over a wide continuum, and so there are no rigid boundaries between the different types of lustre. (For this reason, different sources can often describe the same mineral differently. This ambiguity is further complicated by lustre's ability to vary widely within a particular mineral species). The terms are frequently combined to describe intermediate types of lustre (for example, a "vitreous greasy" lustre). Some minerals exhib ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dispersion (optics)
Dispersion is the phenomenon in which the phase velocity of a wave depends on its frequency. Sometimes the term chromatic dispersion is used to refer to optics specifically, as opposed to wave propagation in general. A medium having this common property may be termed a dispersive medium. Although the term is used in the field of optics to describe light and other electromagnetic waves, dispersion in the same sense can apply to any sort of wave motion such as acoustic dispersion in the case of sound and seismic waves, and in gravity waves (ocean waves). Within optics, dispersion is a property of telecommunication signals along transmission lines (such as microwaves in coaxial cable) or the Pulse (signal processing), pulses of light in optical fiber. In optics, one important and familiar consequence of dispersion is the change in the angle of refraction of different colors of light, as seen in the spectrum produced by a dispersive Prism (optics), prism and in chromatic aberration ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Culet
In gemology, a culet is a flat face on the bottom of a gemstone. During the 14th century, after the adoption of the table cut, a further facet was added to the bottom of the cut parallel to the surface of the table. The term used for these bottom facets derives from the Latin word for bottom, ''culus''. The culet is added largely to protect the integrity of the gemstone. On a diamond, the cleavage plane runs parallel to the octahedral faces, and so any damage to the tip of the diamond could cause a split up the entire length of the pavilion. With other gemstones that are not subject to cleavage, the culet is added to protect the fragility of the pointed tip. The culet has remained optional on many diamond cut A diamond cut is a style or design guide used when shaping a diamond for polishing such as the Brilliant (diamond cut), brilliant cut. Cut refers to shape (Pear cut, pear, oval), and also the symmetry, proportioning and polish of a diamond. The ...s up to the p ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nuremberg
Nuremberg (, ; ; in the local East Franconian dialect: ''Nämberch'' ) is the Franconia#Towns and cities, largest city in Franconia, the List of cities in Bavaria by population, second-largest city in the States of Germany, German state of Bavaria, and its 544,414 (2023) inhabitants make it the List of cities in Germany by population, 14th-largest city in Germany. Nuremberg sits on the Pegnitz (river), Pegnitz, which carries the name Regnitz from its confluence with the Rednitz in Fürth onwards (), and on the Rhine–Main–Danube Canal, that connects the North Sea to the Black Sea. Lying in the Bavarian Regierungsbezirk, administrative region of Middle Franconia, it is the largest city and unofficial capital of the entire cultural region of Franconia. The city is surrounded on three sides by the , a large forest, and in the north lies (''garlic land''), an extensive vegetable growing area and cultural landscape. The city forms a continuous conurbation with the neighbouring ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Guild
A guild ( ) is an association of artisans and merchants who oversee the practice of their craft/trade in a particular territory. The earliest types of guild formed as organizations of tradespeople belonging to a professional association. They sometimes depended on grants of letters patent from a monarch or other ruler to enforce the flow of trade to their self-employed members, and to retain ownership of tools and the supply of materials, but most were regulated by the local government. Guild members found guilty of cheating the public would be fined or banned from the guild. A lasting legacy of traditional guilds are the guildhalls constructed and used as guild meeting-places. Typically the key "privilege" was that only guild members were allowed to sell their goods or practice their skill within the city. There might be controls on minimum or maximum prices, hours of trading, numbers of apprentices, and many other things. Critics argued that these rules reduced Free market, fre ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Octahedron
In geometry, an octahedron (: octahedra or octahedrons) is any polyhedron with eight faces. One special case is the regular octahedron, a Platonic solid composed of eight equilateral triangles, four of which meet at each vertex. Many types of irregular octahedra also exist, including both convex set, convex and non-convex shapes. Combinatorially equivalent to the regular octahedron The following polyhedra are combinatorially equivalent to the regular octahedron. They all have six vertices, eight triangular faces, and twelve edges that correspond one-for-one with the features of it: * Triangular antiprisms: Two faces are equilateral, lie on parallel planes, and have a common axis of symmetry. The other six triangles are isosceles. The regular octahedron is a special case in which the six lateral triangles are also equilateral. * Tetragonal bipyramids, in which at least one of the equatorial quadrilaterals lies on a plane. The regular octahedron is a special case in which all thr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
