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Topaz (Ruby)
Topaz is a silicate mineral made of aluminium, aluminum and fluorine with the chemical formula aluminium, Alsilicon, Sioxygen, O(fluorine, F, hydroxide, OH). It is used as a gemstone in jewelry and other adornments. Common topaz in its natural state is colorless, though trace element impurities can make it pale blue or golden-brown to yellow-orange. Topaz is often treated with heat or radiation to make it a deep blue, reddish-orange, pale green, pink, or purple. Topaz is a nesosilicate mineral, and more specifically, an aluminosilicate mineral. It is one of the hardest naturally occurring minerals and has a relatively low index of refraction. It has the orthorhombic crystal system and a dipyramidial crystal class. It occurs in many places in the world. Some of the most popular places where topaz is sourced are Brazil and Russia. Topaz is often mined in open pit or alluvial settings. Etymology The word "topaz" is usually believed to be derived (via Old French: Topace and Latin: ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Silicate Mineral
Silicate minerals are rock-forming minerals made up of silicate groups. They are the largest and most important class of minerals and make up approximately 90 percent of Earth's crust. In mineralogy, the crystalline forms of silica (silicon dioxide, ) are usually considered to be Silicate mineral#Tectosilicates, tectosilicates, and they are classified as such in the Dana system (75.1). However, the Nickel-Strunz system classifies them as oxide minerals (4.DA). Silica is found in nature as the mineral quartz, and its polymorphism (materials science), polymorphs. On Earth, a wide variety of silicate minerals occur in an even wider range of combinations as a result of the processes that have been forming and re-working the crust for billions of years. These processes include partial melting, crystallization, fractionation, metamorphism, weathering, and diagenesis. Living organisms also contribute to this carbonate–silicate cycle, geologic cycle. For example, a type of plankton ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pliny The Elder
Gaius Plinius Secundus (AD 23/24 79), known in English as Pliny the Elder ( ), was a Roman Empire, Roman author, Natural history, naturalist, and naval and army commander of the early Roman Empire, and a friend of the Roman emperor, emperor Vespasian. He wrote the encyclopedic (''Natural History''), a comprehensive thirty-seven-volume work covering a vast array of topics on human knowledge and the natural world, which became an editorial model for encyclopedias. He spent most of his spare time studying, writing, and investigating natural and geographic phenomena in the field. Among Pliny's greatest works was the twenty-volume ''Bella Germaniae'' ("The History of the German Wars"), which is Lost literary work, no longer extant. ''Bella Germaniae'', which began where Aufidius Bassus' ''Libri Belli Germanici'' ("The War with the Germans") left off, was used as a source by other prominent Roman historians, including Plutarch, Tacitus, and Suetonius. Tacitus may have used ''Bella Ger ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Alexander Polyhistor
Lucius Cornelius Alexander Polyhistor (; flourished in the first half of the 1st century BC; also called Alexander of Miletus) was a Greek scholar who was enslaved by the Romans during the Mithridatic War and taken to Rome as a tutor. After his release, he continued to live in Italy as a Roman citizen. He was so productive as a writer that he earned the surname '' Polyhistor'' (very learned). The majority of his writings are now lost, but the fragments that remain shed valuable light on antiquarian and eastern Mediterranean subjects. Among his works were historical and geographical accounts of nearly all the countries of the ancient world, and the book ''Upon the Jews'' () which excerpted many works which might otherwise be unknown. Life The Suda is the main source of information about Alexander's life. He was born in Miletus, Asia Minor, between 110 and 105 BC and educated by Crates of Mallus in Pergamon, before being captured in the Mithridatic War and brought to Rome as a sl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tamraparni
Tamraparni (Sanskrit for "with copper leaves" or "red-leaved") is an older name for multiple distinct places, including Sri Lanka, Tirunelveli in India, and the Thamirabarani River that flows through Tirunelveli in Tamil Nadu. As a name for Sri Lanka The rock edicts of the 3rd century BCE Indian emperor Ashoka mention the word Tamraparni (as "Tambapanni") in connection with his foreign missions. One edict states that his ''dhamma vijaya'' (victory through dhamma) prevailed in frontier kingdoms of the Choda (Cholas), Pada (Pandyas), and as far as Tambapanni. This seems to be a reference to Sri Lanka, as the Buddhist chronicles of Sri Lanka mention that a port city called Tammapanni was established there during the reign of the legendary king Vijaya. The city was called "Tammena" during the reign of Vijaya's successor Panduvasdeva and "Tammapanni" during the reign of Ashoka's missionary son Mahendra. According to these chronicles, the place was so called because its dust stuck ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Olivine
The mineral olivine () is a magnesium iron Silicate minerals, silicate with the chemical formula . It is a type of Nesosilicates, nesosilicate or orthosilicate. The primary component of the Earth's upper mantle (Earth), upper mantle, it is a common mineral in Earth's subsurface, but weathers quickly on the surface. Olivine has many uses, such as the gemstone peridot (or chrysolite), as well as industrial applications like metalworking processes. The ratio of magnesium to iron varies between the two endmember (mineralogy), endmembers of the solid solution series: forsterite (Mg-endmember: ) and fayalite (Fe-endmember: ). Compositions of olivine are commonly expressed as Mole (unit), molar percentages of forsterite (Fo) and/or fayalite (Fa) (''e.g.'', Fo70Fa30, or just Fo70 with Fa30 implied). Forsterite's melting temperature is unusually high at atmospheric pressure, almost , while fayalite's is much lower – about . Melting temperature varies smoothly between the two end ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Peridot
Peridot ( ), sometimes called chrysolite, is a yellow-green transparent variety of olivine. Peridot is one of the few gemstones that occur in only one color. Peridot can be found in mafic and ultramafic rocks occurring in lava and peridotite xenoliths of the mantle. The gem occurs in silica-deficient rocks such as volcanic basalt and pallasitic meteorites. Along with diamonds, peridot is one of only two gems observed to be formed not in Earth's crust, but in the molten rock of the upper mantle. Gem-quality peridot is rare on Earth's surface due to its susceptibility to alteration during its movement from deep within the mantle and weathering at the surface. Peridot has a chemical formula of . Peridot is one of the birthstones for the month of August. Etymology The origin of the name ''peridot'' is uncertain. The ''Oxford English Dictionary'' suggests an alteration of Anglo– Norman (classical Latin -), a kind of opal, rather than the Arabic word , meaning "gemstone". Th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Red Sea
The Red Sea is a sea inlet of the Indian Ocean, lying between Africa and Asia. Its connection to the ocean is in the south, through the Bab-el-Mandeb Strait and the Gulf of Aden. To its north lie the Sinai Peninsula, the Gulf of Aqaba, and the Gulf of Suez—leading to the Suez Canal. It is underlain by the Red Sea Rift, which is part of the Great Rift Valley. The Red Sea has a surface area of roughly , is about long, and wide at its widest point. It has an average depth of , and in the central Suakin Trough, it reaches its maximum depth of . Approximately 40% of the Red Sea is quite shallow at less than deep and about 25% is less than deep. The extensive shallow shelves are noted for their marine life and corals. More than 1,000 invertebrate species and 200 types of soft and hard coral live in the sea. The Red Sea is the world's northernmost tropical sea and has been designated a Global 200 ecoregion. Extent The International Hydrographic Organization defines the limi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Greek Language
Greek (, ; , ) is an Indo-European languages, Indo-European language, constituting an independent Hellenic languages, Hellenic branch within the Indo-European language family. It is native to Greece, Cyprus, Italy (in Calabria and Salento), southern Albania, and other regions of the Balkans, Caucasus, the Black Sea coast, Asia Minor, and the Eastern Mediterranean. It has the list of languages by first written accounts, longest documented history of any Indo-European language, spanning at least 3,400 years of written records. Its writing system is the Greek alphabet, which has been used for approximately 2,800 years; previously, Greek was recorded in writing systems such as Linear B and the Cypriot syllabary. The Greek language holds a very important place in the history of the Western world. Beginning with the epics of Homer, ancient Greek literature includes many works of lasting importance in the European canon. Greek is also the language in which many of the foundational texts ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Latin
Latin ( or ) is a classical language belonging to the Italic languages, Italic branch of the Indo-European languages. Latin was originally spoken by the Latins (Italic tribe), Latins in Latium (now known as Lazio), the lower Tiber area around Rome, Italy. Through the expansion of the Roman Republic, it became the dominant language in the Italian Peninsula and subsequently throughout the Roman Empire. It has greatly influenced many languages, Latin influence in English, including English, having contributed List of Latin words with English derivatives, many words to the English lexicon, particularly after the Christianity in Anglo-Saxon England, Christianization of the Anglo-Saxons and the Norman Conquest. Latin Root (linguistics), roots appear frequently in the technical vocabulary used by fields such as theology, List of Latin and Greek words commonly used in systematic names, the sciences, List of medical roots, suffixes and prefixes, medicine, and List of Latin legal terms ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Old French
Old French (, , ; ) was the language spoken in most of the northern half of France approximately between the late 8th [2-4; we might wonder whether there's a point at which it's appropriate to talk of the beginnings of French, that is, when it was deemed no longer make to think of the varieties spoken in Gaul as Latin. Although a precise date can't be given, there is a general consensus (see Wright 1982, 1991, Lodge 1993) that an awareness of a vernacular, distinct from Latin, emerged at the end of the eighth century.] and mid-14th centuries. Rather than a unified Dialect#Dialect or language, language, Old French was a Dialect cluster, group of Romance languages, Romance dialects, Mutual intelligibility, mutually intelligible yet Dialect continuum, diverse. These dialects came to be collectively known as the , contrasting with the , the emerging Occitano-Romance languages of Occitania, now the south of France. The mid-14th century witnessed the emergence of Middle French, the lang ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Crystal Class
In crystallography, a crystallographic point group is a three-dimensional point group whose symmetry operations are compatible with a three-dimensional crystallographic lattice. According to the crystallographic restriction it may only contain one-, two-, three-, four- and sixfold rotations or rotoinversions. This reduces the number of crystallographic point groups to 32 (from an infinity of general point groups). These 32 groups are the same as the 32 types of morphological (external) crystalline symmetries derived in 1830 by Johann Friedrich Christian Hessel from a consideration of observed crystal forms. In 1867 Axel Gadolin, who was unaware of the previous work of Hessel, found the crystallographic point groups independently using stereographic projection to represent the symmetry elements of the 32 groups. In the classification of crystals, to each space group is associated a crystallographic point group by "forgetting" the translational components of the symmetry operation ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
