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Flint occurs chiefly as nodules and masses in sedimentary rocks, such as chalks and limestones. [3] [4] Inside the nodule, flint is usually dark grey or black, green, white, or brown in colour, and has a glassy or waxy appearance. A thin, oxidised layer on the outside of the nodules is usually different in colour, typically white and rough in ...
Nodule is also used for widely scattered concretionary lumps of manganese, cobalt, iron, and nickel found on the floors of the world's oceans. This is especially true of manganese nodules. Manganese and phosphorite nodules form on the seafloor and are syndepositional in origin. Thus, technically speaking, they are concretions instead of nodules ...
Paramoudras, paramoudra flints, pot stones or potstones are flint nodules found mainly in parts of north-west Europe: Norfolk (United Kingdom), Ireland, Denmark, Spain and Germany. In Norfolk they are known as pot stones and can be found on the beach below Beeston Bump just outside Beeston Regis. In Ireland they are known as paramoudras.
The hydrous iron sulfate forms a white powder consisting of the mineral melanterite, FeSO 4 ·7H 2 O. [13] This disintegration of marcasite in mineral collections is known as " pyrite decay ". When a specimen goes through pyrite decay, the marcasite reacts with moisture and oxygen in the air, the sulfur oxidizing and combining with water to ...
Iron formations can be divided into subdivisions known as: banded iron formations (BIFs) and granular iron formations (GIFs). [ 3 ] The above classification scheme is the most commonly used and accepted, though sometimes an older system is used which divides iron-rich sedimentary rocks into three categories: bog iron deposits , ironstones , and ...
Iron poisoning typically occurs from ingestion of excess iron that results in acute toxicity. Mild symptoms which occur within hours include vomiting, diarrhea, abdominal pain, and drowsiness. [1] In more severe cases, symptoms can include tachypnea, low blood pressure, seizures, or coma. [2]
Transfusional hemosiderosis is the accumulation of iron in the body due to frequent blood transfusions. Iron accumulates in the liver and heart, but also endocrine organs. Frequent blood transfusions may be given to many patients, such as those with thalassemia, sickle cell disease, leukemia, aplastic anemia, or myelodysplastic syndrome, among ...
Grime's Graves is a large Neolithic flint mining complex in Norfolk, England.It lies 8 km (5.0 mi) north east from Brandon, Suffolk in the East of England.It was worked between c. 2600 and c. 2300 BCE, although production may have continued through the Bronze and Iron Ages and later, owing to the low cost of flint compared with metals.