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Belomorite
Belomorite ( — from the toponym), sometimes ''peristerite'' or ''moonstone'', also ''murchisonite'', ''Ceylon opal'', ''hecatolite'' — a decorative variety of albite (oligoclase) of white or light gray color with a distinct iridescence effect. By composition, belomorite belongs to the feldspar family; it is a sodium aluminosilicate from the plagioclase group, in most cases belonging to the isomorphic series albite (Ab) — anorthite (An) with an approximate percentage of 70Ab-30An. The name “belomorite” was given to this variety of albite by academician Alexander Fersman in 1925, based on the location of its discovery near the shore of the White Sea, and also by association — for the similarity of iridescence colors with the shades of sea water. The best varieties of belomorite are translucent or transparent, they have a pearl-glass luster and iridescence in blue, gray-blue, violet-blue, greenish-blue or pale violet tones. The most famous deposits of this gem are in the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Moonstone (gemstone)
Moonstone is a sodium potassium aluminium silicate minerals, silicate ((Na,K)AlSi3O8) of the feldspar group that displays a pearly and opalescence, opalescent Lustre (mineralogy)#Schiller, schiller. An alternative name for moonstone is hecatolite (from goddess Hecate). Etymology The name ''moonstone'' derives from the stone's characteristic visual effect, called adularescence (or schiller), which produces a milky, bluish interior light. This effect is caused by light diffraction through alternating layers of orthoclase and albite within the stone. The diffracted light varies from white to blue, depending on the thinness of the albite layers. More technically, this micro-structure consists of regular exsolution layers (lamellae) of different alkali feldspars (orthoclase and sodium-rich plagioclase). Polished moonstones often display chatoyancy ("cat's eye" effect), where a luminous streak appears through the stone. Asterism (gemology), Asterism is rare and produces four-legged ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cabochon
A cabochon (; ) is a gemstone that has been shaped and polished, as opposed to faceted. The resulting form is usually a convex (rounded) obverse with a flat reverse. Cabochon was the default method of preparing gemstones before gemstone cutting developed. Application Cutting ''en cabochon'' (French: "in the manner of a cabochon") is usually applied to opaque gems, while faceting is usually used for transparent stones. Hardness is also taken into account as softer gemstones with a hardness lower than 7 on the Mohs hardness scale are easily scratched, mainly by silicon dioxide in dust and grit. This would quickly make translucent gems unattractive—instead they are polished as cabochons, making the scratches less evident. In asteriated stones such as star sapphires and chatoyant stones such as cat's eye chrysoberyl, a domed cabochon cut can show the star or eye, which would not be visible in a faceted cut. The usual shape for cutting cabochons is an ellipse, because the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Spinodal Decomposition
Spinodal decomposition is a mechanism by which a single thermodynamic Phase (matter), phase spontaneously separates into two phases (without nucleation). Decomposition occurs when there is no Thermodynamics, thermodynamic barrier to phase separation. As a result, phase separation via decomposition does not require the nucleation events resulting from thermodynamic fluctuations, which normally trigger phase separation. Spinodal decomposition is observed when mixtures of metals or polymers separate into two co-existing phases, each rich in one species and poor in the other. When the two phases emerge in approximately equal proportion (each occupying about the same volume or area), characteristic intertwined structures are formed that gradually coarsen (see animation). The dynamics of spinodal decomposition is commonly modeled using the Cahn–Hilliard equation. Spinodal decomposition is fundamentally different from nucleation and growth. When there is a nucleation barrier to the form ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cleavage (crystal)
Cleavage, in mineralogy and materials science, is the tendency of crystalline materials to split along definite crystallographic structural planes. These planes of relative weakness are a result of the regular locations of atoms and ions in the crystal, which create smooth repeating surfaces that are visible both in the microscope and to the naked eye. If bonds in certain directions are weaker than others, the crystal will tend to split along the weakly bonded planes. These flat breaks are termed "cleavage".Hurlbut, Cornelius S.; Klein, Cornelis, 1985, '' Manual of Mineralogy'', 20th ed., Wiley, The classic example of cleavage is mica, which cleaves in a single direction along the basal pinacoid, making the layers seem like pages in a book. In fact, mineralogists often refer to "books of mica". Diamond and graphite provide examples of cleavage. Each is composed solely of a single element, carbon. In diamond, each carbon atom is bonded to four others in a tetrahedral patter ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Moonstone (iridescent Peristerite-oligoclase Feldspar) (Chupa Pegmatite Field, Mesoproterozoic, 1
Moonstone may refer to: * Moonstone (gemstone), a sodium potassium aluminium silicate * Moonstone as belomorite, one of the varieties of plagioclase * Moon rock, a rock which was once part of the Moon Arts and entertainment Fictional entities * Moonstone, Colorado, a town in '' The Song of the Lark'' by Willa Cather * Moonstone (comics), the name of two Marvel Comics universe characters * Moonstone, a plot element in season 2 of ''The Vampire Diaries'' * Moonstone Opal, a plot element in ''Tangled The Series'' * Moonstone, a setting in Erin Hunter's ''Warriors'' story arc * Moonstone, an artifact in the ''Lone Wolf'' gamebooks Film and television * ''The Moonstone'' (1909 film), by William Nicholas Selig, probably lost * ''The Moonstone'' (1915 film), by Frank Hall Crane * ''The Moonstone'' (1934 film), by Reginald Barker * ''The Moonstone'' (1996 film), a TV film * ''The Moonstone'' (1959 TV series), a British miniseries * ''The Moonstone'' (1972 TV series), a British m ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Crystallography
Crystallography is the branch of science devoted to the study of molecular and crystalline structure and properties. The word ''crystallography'' is derived from the Ancient Greek word (; "clear ice, rock-crystal"), and (; "to write"). In July 2012, the United Nations recognised the importance of the science of crystallography by proclaiming 2014 the International Year of Crystallography.UN announcement "International Year of Crystallography" iycr2014.org. 12 July 2012 Crystallography is a broad topic, and many of its subareas, such as X-ray crystallography, are themselves important scientific topics. Crystallography ranges from the fundamentals of crystal structure to the mathematics of Crystal system, crystal geometry, including those that are Aperiodic crystal, not periodic or quasi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Greece
Greece, officially the Hellenic Republic, is a country in Southeast Europe. Located on the southern tip of the Balkan peninsula, it shares land borders with Albania to the northwest, North Macedonia and Bulgaria to the north, and Turkey to the east. The Aegean Sea lies to the east of the Geography of Greece, mainland, the Ionian Sea to the west, and the Sea of Crete and the Mediterranean Sea to the south. Greece has the longest coastline on the Mediterranean Basin, spanning List of islands of Greece, thousands of islands and nine Geographic regions of Greece, traditional geographic regions. It has a population of over 10 million. Athens is the nation's capital and List of cities and towns in Greece, largest city, followed by Thessaloniki and Patras. Greece is considered the cradle of Western culture, Western civilisation and the birthplace of Athenian democracy, democracy, Western philosophy, Western literature, historiography, political science, major History of science in cl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lakmos
Lakmos () is a mountain in eastern Ioannina and western Trikala regional units. The mountain is a part of the Pindus mountain range. Its highest peak is the ''Peristeri'', at 2,295 m elevation. It stretches from the village Krapsi in the west to near Metsovo in the east, over a length of about . The nearest mountains are the Athamanika to the south, the Lygkos to the north and the Mitsikeli to the west. It is drained by the river Arachthos and its tributaries to the north, west and south, and by the Acheloos to the east. The nearest town is Metsovo, at its northeastern end. Other places in the mountains are Anthousa in the southeast, Anthochori in the north, Megali Gotista in the west and Vathypedo in the southwest. The A2 Egnatia Odos motorway (Igoumenitsa - Ioannina - Kozani - Thessaloniki - Alexandroupolis Alexandroupolis (, ) or Alexandroupoli (, ) is a city in Greece and the capital of the Evros (regional unit), Evros regional unit. It is the largest city in Gre ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mica
Micas ( ) are a group of silicate minerals whose outstanding physical characteristic is that individual mica crystals can easily be split into fragile elastic plates. This characteristic is described as ''perfect basal cleavage''. Mica is common in igneous and metamorphic rock and is occasionally found as small flakes in sedimentary rock. It is particularly prominent in many granites, pegmatites, and schists, and "books" (large individual crystals) of mica several feet across have been found in some pegmatites. Micas are used in products such as drywalls, paints, and fillers, especially in parts for automobiles, roofing, and in electronics. The mineral is used in cosmetics and food to add "shimmer" or "frost". Properties and structure The mica group comprises 37 phyllosilicate minerals. All crystallize in the monoclinic system, with a tendency towards pseudohexagonal crystals, and are similar in structure but vary in chemical composition. Micas are translucent to opa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sevastopol
Sevastopol ( ), sometimes written Sebastopol, is the largest city in Crimea and a major port on the Black Sea. Due to its strategic location and the navigability of the city's harbours, Sevastopol has been an important port and naval base throughout its history. Since the city's founding in 1783 it has been a major base for Russia's Black Sea Fleet. During the Cold War of the 20th century, it was a closed city. The total administrative area is and includes a significant amount of rural land. The urban population, largely concentrated around Sevastopol Bay, is 479,394, and the total population is 547,820. Sevastopol, along with the rest of Crimea, is internationally recognised as part of Ukraine, and under the Ukrainian legal framework, it is administratively one of two cities with special status (the other being Kyiv). However, it has been occupied by Russia since 27 February 2014, before Russia annexed Crimea on 18 March 2014 and gave it the status of a federal city of R ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Black Sea
The Black Sea is a marginal sea, marginal Mediterranean sea (oceanography), mediterranean sea lying between Europe and Asia, east of the Balkans, south of the East European Plain, west of the Caucasus, and north of Anatolia. It is bounded by Bulgaria, Georgia (country), Georgia, Romania, Russia, Turkey, and Ukraine. The Black Sea is Inflow (hydrology), supplied by major rivers, principally the Danube, Dnieper and Dniester. Consequently, while six countries have a coastline on the sea, its drainage basin includes parts of 24 countries in Europe. The Black Sea, not including the Sea of Azov, covers , has a maximum depth of , and a volume of . Most of its coasts ascend rapidly. These rises are the Pontic Mountains to the south, bar the southwest-facing peninsulas, the Caucasus Mountains to the east, and the Crimean Mountains to the mid-north. In the west, the coast is generally small floodplains below foothills such as the Strandzha; Cape Emine, a dwindling of the east end ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lustre (mineralogy)
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] |
