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Calcareous Sinter
Calcareous sinter is a freshwater calcium carbonate deposit, also known as calc-sinter. Deposits are characterised by low porosity and well-developed lamination, often forming crusts or sedimentary rock layers. Calcareous sinter should not be confused with siliceous sinter, which the term sinter more frequently refers to. It has been suggested that the term "sinter" should be restricted to siliceous spring deposits and be dropped for calcareous deposits entirely. Features Calcareous sinter is characterised by laminations of prismatic crystals growing perpendicular to the substrate; laminations are separated by thin layers of microcrystalline carbonate. Calcareous sinter is porous due to the calcareous crystals enclosing many small cavities. Macrophytes are absent, consequently porosity is very low. Exclusion of species is due either to high temperature (travertine), high pH/ionic strength (tufa) or absence of light (speleothems). Pedley (1990) suggests the term be abandoned in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Carbonate Minerals
Carbonate minerals are those minerals containing the carbonate ion, . Carbonate divisions Anhydrous carbonates *Calcite group: trigonal **Calcite CaCO3 **Gaspéite (Ni,Mg,Fe2+)CO3 **Magnesite MgCO3 **Otavite CdCO3 **Rhodochrosite MnCO3 **Siderite FeCO3 **Smithsonite ZnCO3 **Spherocobaltite CoCO3 *Aragonite group: orthorhombic **Aragonite CaCO3 **Cerussite PbCO3 **Strontianite SrCO3 **Witherite BaCO3 **Rutherfordine UO2CO3 **Natrite Na2CO3 Anhydrous carbonates with compound formulas *Dolomite group: trigonal **Ankerite CaFe(CO3)2 **Dolomite (mineral), Dolomite CaMg(CO3)2 **Huntite Mg3Ca(CO3)4 **Minrecordite CaZn(CO3)2 **Barytocalcite BaCa(CO3)2 Carbonates with hydroxyl or halogen *Carbonate with hydroxide: monoclinic **Azurite Cu3(CO3)2(OH)2 **Hydrocerussite Pb3(CO3)2(OH)2 **Malachite Cu2CO3(OH)2 **Rosasite (Cu,Zn)2CO3(OH)2 **Phosgenite Pb2(CO3)Cl2 **Hydrozincite Zn5(CO3)2(OH)6 **Aurichalcite (Zn,Cu)5(CO3)2(OH)6 Hydrated carbonates *Hydromagnesite Mg5(CO3)4(OH)2.4H2O *Ikaite ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Calcium Minerals
Calcium is a chemical element with the symbol Ca and atomic number 20. As an alkaline earth metal, calcium is a reactive metal that forms a dark oxide-nitride layer when exposed to air. Its physical and chemical properties are most similar to its heavier homologues strontium and barium. It is the fifth most abundant element in Earth's crust, and the third most abundant metal, after iron and aluminium. The most common calcium compound on Earth is calcium carbonate, found in limestone and the fossilised remnants of early sea life; gypsum, anhydrite, fluorite, and apatite are also sources of calcium. The name derives from Latin ''calx'' " lime", which was obtained from heating limestone. Some calcium compounds were known to the ancients, though their chemistry was unknown until the seventeenth century. Pure calcium was isolated in 1808 via electrolysis of its oxide by Humphry Davy, who named the element. Calcium compounds are widely used in many industries: in foods and pharmaceu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Petrifying Well
A petrifying well is a well or other body of water which gives objects a stone-like appearance. If an object is placed into such a well and left there for a period of months or years, the object acquires a stony exterior. Nature If an object is placed into such a well and left there for a period of weeks or months the object acquires a stony exterior. At one time this property was believed to be a result of magic or witchcraft, but it is an entirely natural phenomenon and due to a process of evaporation and deposition in waters with an unusually high mineral content. This process of petrifying is not to be confused with petrification wherein the constituent molecules of the original object are replaced (and not merely overlaid) with molecules of stone or mineral. Examples Notable examples of petrifying wells in England are the spring at Mother Shipton's Cave in Knaresborough and Matlock Bath, in Derbyshire. While in Ireland, such wells were noted by John Rutty on Howth Head,Ru ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Norwich Cathedral
Norwich Cathedral is an Anglican cathedral in Norwich, Norfolk, dedicated to the Holy and Undivided Trinity. It is the cathedral church for the Church of England Diocese of Norwich and is one of the Norwich 12 heritage sites. The cathedral was begun in 1096 and constructed out of flint and mortar and faced with a cream-coloured Caen limestone. An Anglo-Saxon settlement and two churches were demolished to make room for the buildings. The cathedral was completed in 1145 with the Norman tower still seen today topped with a wooden spire covered with lead. Episodes of damage necessitated rebuilding and the stone spire was erected in 1480. The bosses of Norwich Cathedral are one of the world's greatest mediaeval sculptural treasures that survived the iconoclasm of the Tudor and English Civil War periods.The bosses in the cloisters include hundreds that are carved and ornately painted. Norwich Cathedral has the second largest cloisters in England, only exceeded by those at S ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rochester Cathedral
Rochester Cathedral, formally the Cathedral Church of Christ and the Blessed Virgin Mary, is an English church of Norman architecture in Rochester, Medway, Rochester, Kent. The church is the cathedral of the Diocese of Rochester in the Church of England and the Cathedra, seat (''cathedra'') of the Bishop of Rochester, the second oldest bishopric in England after that of the Archbishop of Canterbury. The edifice is a Listed building, Grade I listed building (number 1086423). History Anglo-Saxon establishment The Rochester diocese was founded by Justus, one of the missionary, missionaries who accompanied Augustine of Canterbury to convert the pagan southern English to Christianity in the early 7th century. As the first Bishop of Rochester, Justus was given permission by King Æthelberht of Kent to establish a church dedicated to Andrew the Apostle (like the monastery at Rome where Augustine and Justus had set out for England) on the site of the present cathedral, which was ma ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Canterbury Cathedral
Canterbury Cathedral in Canterbury, Kent, is one of the oldest and most famous Christian structures in England. It forms part of a World Heritage Site. It is the cathedral of the Archbishop of Canterbury, currently Justin Welby, leader of the Church of England and symbolic leader of the worldwide Anglican Communion. Its formal title is the Cathedral and Metropolitical Church of Christ at Canterbury. Founded in 597, the cathedral was completely rebuilt between 1070 and 1077. The east end was greatly enlarged at the beginning of the 12th century and largely rebuilt in the Gothic style following a fire in 1174, with significant eastward extensions to accommodate the flow of pilgrims visiting the shrine of Thomas Becket, the archbishop who was murdered in the cathedral in 1170. The Norman nave and transepts survived until the late 14th century when they were demolished to make way for the present structures. Before the English Reformation the cathedral was part of a Benedictin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Marble
Marble is a metamorphic rock composed of recrystallized carbonate minerals, most commonly calcite or dolomite. Marble is typically not foliated (layered), although there are exceptions. In geology, the term ''marble'' refers to metamorphosed limestone, but its use in stonemasonry more broadly encompasses unmetamorphosed limestone. Marble is commonly used for sculpture and as a building material. Etymology The word "marble" derives from the Ancient Greek (), from (), "crystalline rock, shining stone", perhaps from the verb (), "to flash, sparkle, gleam"; R. S. P. Beekes has suggested that a " Pre-Greek origin is probable". This stem is also the ancestor of the English word "marmoreal," meaning "marble-like." While the English term "marble" resembles the French , most other European languages (with words like "marmoreal") more closely resemble the original Ancient Greek. Physical origins Marble is a rock resulting from metamorphism of sedimentary carbonate rocks, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Onyx
Onyx primarily refers to the parallel banded variety of chalcedony, a silicate mineral. Agate and onyx are both varieties of layered chalcedony that differ only in the form of the bands: agate has curved bands and onyx has parallel bands. The colors of its bands range from black to almost every color. Commonly, specimens of onyx contain bands of black and/or white. Onyx, as a descriptive term, has also been applied to parallel banded varieties of alabaster, marble, calcite, obsidian and opal, and misleadingly to materials with contorted banding, such as "Cave Onyx" and "Mexican Onyx". Etymology ''Onyx'' comes through Latin (of the same spelling), from the Ancient Greek , meaning "claw" or "fingernail". Onyx with flesh-colored and white bands can sometimes resemble a fingernail. The English word "nail" is cognate with the Greek word. Varieties Onyx is formed of bands of chalcedony in alternating colors. It is cryptocrystalline, consisting of fine intergrowths of the silica ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Norman Architecture
The term Norman architecture is used to categorise styles of Romanesque architecture developed by the Normans in the various lands under their dominion or influence in the 11th and 12th centuries. In particular the term is traditionally used for English Romanesque architecture. The Normans introduced large numbers of castles and fortifications including Norman keeps, and at the same time monasteries, abbeys, churches and cathedrals, in a style characterised by the usual Romanesque rounded arches (particularly over windows and doorways) and especially massive proportions compared to other regional variations of the style. Origins These Romanesque styles originated in Normandy and became widespread in northwestern Europe, particularly in England, which contributed considerable development and where the largest number of examples survived. At about the same time, a Norman dynasty that ruled in Sicily produced a distinctive variation–incorporating Byzantine and Sarace ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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