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Powder Glass Beads
Powder glass beads are a type of necklace ornamentation. The earliest such beads were discovered during archaeological excavations at Mapungubwe in South Africa, and dated to between 970-1000 CE. Manufacturing of the powder glass beads is now concentrated in West Africa, particularly in the Ghana area. The origins of beadmaking in Ghana are unknown, but the great majority of powder glass beads produced today is made by Ashanti and Krobo craftsmen and women. Krobo bead making has been documented to date from as early as the 1920s but despite limited archaeological evidence, it is believed that Ghanaian powder glass bead making dates further back. Bead making in Ghana was first documented by John Barbot in 1746. Beads still play important roles in Krobo society, be it in rituals of birth, coming of age, marriage, or death. Powder glass beads are made from finely ground glass, the main source being broken and unusable bottles and a great variety of other scrap glasses. Special glass ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Coral (precious)
Precious coral, or red coral, is the common name given to a genus of marine corals, ''Corallium''. The distinguishing characteristic of precious corals is their durable and intensely colored red or pink-orange skeleton, which is used for making jewelry. Habitat Red corals grow on rocky seabottom with low sedimentation, typically in dark environments—either in the depths or in dark caverns or crevices. The original species, ''C. rubrum'' (formerly ''Gorgonia nobilis''), is found mainly in the Mediterranean Sea. It grows at depths from 10 to 300 meters below sea level, although the shallower of these habitats have been largely depleted by harvesting. In the underwater caves of Alghero, Sardinia (the "Coral Riviera") it grows at depth from 4 to 35 meters. The same species is also found at Atlantic sites near the Strait of Gibraltar, at the Cape Verde Islands and off the coast of southern Portugal. Other ''Corallium'' species are native to the western Pacific, notably ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nigeria
Nigeria ( ), , ig, Naìjíríyà, yo, Nàìjíríà, pcm, Naijá , ff, Naajeeriya, kcg, Naijeriya officially the Federal Republic of Nigeria, is a country in West Africa. It is situated between the Sahel to the north and the Gulf of Guinea to the south in the Atlantic Ocean. It covers an area of , and with a population of over 225 million, it is the List of African countries by population, most populous country in Africa, and the List of countries and dependencies by population, world's sixth-most populous country. Nigeria borders Niger in Niger–Nigeria border, the north, Chad in Chad–Nigeria border, the northeast, Cameroon in Cameroon–Nigeria border, the east, and Benin in Benin–Nigeria border, the west. Nigeria is a Federation, federal republic comprising of States of Nigeria, 36 states and the Federal Capital Territory, Nigeria, Federal Capital Territory, where the capital, Abuja, is located. The List of Nigerian cities by population, largest city in Nigeria ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Yoruba People
The Yoruba people (, , ) are a West African ethnic group that mainly inhabit parts of Nigeria, Benin, and Togo. The areas of these countries primarily inhabited by Yoruba are often collectively referred to as Yorubaland. The Yoruba constitute more than 42 million people in Africa, are a few hundred thousand outside the continent, and bear further representation among members of the African diaspora. The vast majority of the Yoruba population is today within the country of Nigeria, where they make up 21% of the country's population according to CIA estimations, making them one of the largest ethnic groups in Africa. Most Yoruba people speak the Yoruba language, which is the Niger-Congo language with the largest number of native or L1 speakers. In Africa, the Yoruba are contiguous with the Yoruboid Itsekiri to the south-east in the northwest Niger Delta, Bariba to the northwest in Benin and Nigeria, the Nupe to the north, and the Ebira to the northeast in central Nigeria ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Opacity (optics)
Opacity is the measure of impenetrability to electromagnetic or other kinds of radiation, especially visible light. In radiative transfer, it describes the absorption and scattering of radiation in a medium, such as a plasma, dielectric, shielding material, glass, etc. An opaque object is neither transparent (allowing all light to pass through) nor translucent (allowing some light to pass through). When light strikes an interface between two substances, in general some may be reflected, some absorbed, some scattered, and the rest transmitted (also see refraction). Reflection can be diffuse, for example light reflecting off a white wall, or specular, for example light reflecting off a mirror. An opaque substance transmits no light, and therefore reflects, scatters, or absorbs all of it. Both mirrors and carbon black are opaque. Opacity depends on the frequency of the light being considered. For instance, some kinds of glass, while transparent in the visual range, are larg ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Horizontal Plane
In astronomy, geography, and related sciences and contexts, a '' direction'' or '' plane'' passing by a given point is said to be vertical if it contains the local gravity direction at that point. Conversely, a direction or plane is said to be horizontal if it is perpendicular to the vertical direction. In general, something that is vertical can be drawn from up to down (or down to up), such as the y-axis in the Cartesian coordinate system. Historical definition The word ''horizontal'' is derived from the Latin , which derives from the Greek , meaning 'separating' or 'marking a boundary'. The word ''vertical'' is derived from the late Latin ', which is from the same root as ''vertex'', meaning 'highest point' or more literally the 'turning point' such as in a whirlpool. Girard Desargues defined the vertical to be perpendicular to the horizon in his 1636 book ''Perspective''. Geophysical definition The plumb line and spirit level In physics, engineering and construction, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Equator
The equator is a circle of latitude, about in circumference, that divides Earth into the Northern and Southern hemispheres. It is an imaginary line located at 0 degrees latitude, halfway between the North and South poles. The term can also be used for any other celestial body that is roughly spherical. In spatial (3D) geometry, as applied in astronomy, the equator of a rotating spheroid (such as a planet) is the parallel (circle of latitude) at which latitude is defined to be 0°. It is an imaginary line on the spheroid, equidistant from its poles, dividing it into northern and southern hemispheres. In other words, it is the intersection of the spheroid with the plane perpendicular to its axis of rotation and midway between its geographical poles. On and near the equator (on Earth), noontime sunlight appears almost directly overhead (no more than about 23° from the zenith) every day, year-round. Consequently, the equator has a rather stable daytime temperature ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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