Ballas (or shot bort ) is a diamond industry term for roughly spherical shards of non-gem-grade diamond, mostly mined in Brazil and South Africa. [1]
A ballas is an aggregate of diamond grains concentrically arranged with radiating structure into a roughly spherical stone with a fibrous texture and without throughgoing cleavage planes. Tougher and more difficult to cleave than crystalline stones, ballas are used as industrial diamonds.
A ball is a round object with several uses. It is used in ball games, where the play of the game follows the state of the ball as it is hit, kicked or thrown by players. Balls can also be used for simpler activities, such as catch or juggling. Balls made from hard-wearing materials are used in engineering applications to provide very low friction bearings, known as ball bearings. Black-powder weapons use stone and metal balls as projectiles.
Diamond is a solid form of the element carbon with its atoms arranged in a crystal structure called diamond cubic. 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. They are also the reason that diamond anvil cells can subject materials to pressures found deep in the Earth.
The Mohs scale of mineral hardness is a qualitative ordinal scale, from 1 to 10, characterizing scratch resistance of minerals through the ability of harder material to scratch softer material.
Lapidary is the practice of shaping stone, minerals, or gemstones into decorative items such as cabochons, engraved gems, and faceted designs. A person who practices lapidary is known as a lapidarist. A lapidarist uses the lapidary techniques of cutting, grinding, and polishing. Hardstone carving requires specialized carving techniques.
Spherical Earth or Earth's curvature refers to the approximation of figure of the Earth as a sphere. The earliest documented mention of the concept dates from around the 5th century BC, when it appears in the writings of Greek philosophers. In the 3rd century BC, Hellenistic astronomy established the roughly spherical shape of Earth as a physical fact and calculated the Earth's circumference. This knowledge was gradually adopted throughout the Old World during Late Antiquity and the Middle Ages. A practical demonstration of Earth's sphericity was achieved by Ferdinand Magellan and Juan Sebastián Elcano's circumnavigation (1519–1522).
A geode is a geological secondary formation within sedimentary and volcanic rocks. Geodes are hollow, vaguely spherical rocks, in which masses of mineral matter are secluded. The crystals are formed by the filling of vesicles in volcanic and subvolcanic rocks by minerals deposited from hydrothermal fluids; or by the dissolution of syn-genetic concretions and partial filling by the same or other minerals precipitated from water, groundwater, or hydrothermal fluids.
Lab-grown diamond is diamond that is produced in a controlled technological process. Unlike diamond simulants, synthetic diamonds are composed of the same material as naturally formed diamonds – pure carbon crystallized in an isotropic 3D form – and share identical chemical and physical properties.
Bort, boart, or boort is an umbrella term used in the diamond industry to refer to shards of non-gem-grade/quality diamonds. In the manufacturing and heavy industries, "bort" is used to describe dark, imperfectly formed or crystallized diamonds of varying levels of opacity. The lowest grade, "crushing bort," is crushed by steel mortars and used to make industrial-grade abrasive grits. Small bort crystals are used in drill bits. The Democratic Republic of the Congo provides 75% of the world supply of crushing bort.
Diamond is the allotrope of carbon in which the carbon atoms are arranged in the specific type of cubic lattice called diamond cubic. It is a crystal that is transparent to opaque and which is generally isotropic. Diamond is the hardest naturally occurring material known. Yet, due to important structural brittleness, bulk diamond's toughness is only fair to good. The precise tensile strength of bulk diamond is little known; however, compressive strength up to 60 GPa has been observed, and it could be as high as 90–100 GPa in the form of micro/nanometer-sized wires or needles, with a corresponding maximum tensile elastic strain in excess of 9%. The anisotropy of diamond hardness is carefully considered during diamond cutting. Diamond has a high refractive index (2.417) and moderate dispersion (0.044) properties that give cut diamonds their brilliance. Scientists classify diamonds into four main types according to the nature of crystallographic defects present. Trace impurities substitutionally replacing carbon atoms in a diamond's crystal structure, and in some cases structural defects, are responsible for the wide range of colors seen in diamond. Most diamonds are electrical insulators and extremely efficient thermal conductors. Unlike many other minerals, the specific gravity of diamond crystals (3.52) has rather small variation from diamond to diamond.
Rustication is a range of masonry techniques used in classical architecture giving visible surfaces a finish texture that contrasts with smooth, squared-block masonry called ashlar. The visible face of each individual block is cut back around the edges to make its size and placing very clear. In addition the central part of the face of each block may be given a deliberately rough or patterned surface.
Habiganj, formerly known as Habibganj, is a district in north-eastern Bangladesh, located in the Sylhet Division. It was established as a district in 1984 as a successor to its subdivision status since 1867. It is named after its headquarters, the town of Habiganj.
Optical manufacturing and testing spans an enormous range of manufacturing procedures and optical test configurations.
Superfinishing, also known as micromachining, microfinishing, and short-stroke honing, is a metalworking process that improves surface finish and workpiece geometry. This is achieved by removing just the thin amorphous surface layer left by the last process with an abrasive stone or tape; this layer is usually about 1 μm in magnitude. Superfinishing, unlike polishing which produces a mirror finish, creates a cross-hatch pattern on the workpiece.
Stonesetting is the art of securely setting or attaching gemstones into jewelry.
Mark Alexander Ballas Jr. is an American dancer, choreographer, singer-songwriter, musician, and actor.
Diamond is one of the best-known and most sought-after gemstones. They have been used as decorative items since ancient times.
A computer numerical control (CNC) router is a computer-controlled cutting machine which typically mounts a hand-held router as a spindle which is used for cutting various materials, such as wood, composites, metals, plastics, glass, and foams. CNC routers can perform the tasks of many carpentry shop machines such as the panel saw, the spindle moulder, and the boring machine. They can also cut joinery such as mortises and tenons.
Girl Running on a Balcony is a 1912 painting by Giacomo Balla, one of the forerunners of the Italian movement called Futurism. The piece indicates the artist's growing interests in creative nuances which would later formally be realized as part of the Futurist movement. The artist was heavily influenced by northern Italians' use of Divisionism and the French's better-known pointillism. Created with oil on canvas just on the brink of World War I, the Futurist movement is embodied by a dark optimism for a future of speed, turbulence, chaos, and new beginnings. Most of Giacaomo Balla's pieces allude to the wonder of dynamic movement, and this painting is no exception. The oil painting is now in the Museo del Novecento, in Milan.
Abu Ballas is an archaeological site in the Libyan Desert of Egypt. It lies about 200 km (120 mi) south-west of the Dakhla Oases and consists of two isolated sandstone cones in the otherwise flat desert. Both hills are covered with Egyptian pottery. These vessels were at the beginning of the 20th century often well preserved, but are today - due to modern tourism - very much destroyed. The site was discovered in 1918 and 1923. More recent research was undertaken in the last years.
The pyramid of Naqada, also called the pyramid of Ombos, is part of a group of seven very similar small step pyramids, which were all erected far from the major centres of Egypt and about which very little is known. It is located about 300 metres north of the ruins of the ancient site of Ombos, near the modern city of Naqada in Upper Egypt. The first excavation was undertaken in 1895 by Flinders Petrie and James Edward Quibell.
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