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It is generally glassy or fine-grained in texture, but may be porphyritic, containing larger mineral crystals (phenocrysts) in an otherwise fine-grained groundmass. The mineral assemblage is predominantly quartz, sanidine, and plagioclase. It is the extrusive equivalent of granite.
Galena. Galena, also called lead glance, is the natural mineral form of lead (II) sulfide (PbS). It is the most important ore of lead and an important source of silver. [ 5] Galena is one of the most abundant and widely distributed sulfide minerals. It crystallizes in the cubic crystal system often showing octahedral forms.
Monument of laterite brickstones at Angadipuram, Kerala, India, which commemorates where laterite was first described and discussed by Buchanan-Hamilton in 1807. Laterite is a soil type rich in iron and aluminium and is commonly considered to have formed in hot and wet tropical areas. Nearly all laterites are of rusty-red coloration, because of ...
Volcanogenic massive sulfide ore deposits, also known as VMS ore deposits, are a type of metal sulfide ore deposit, mainly copper - zinc which are associated with and produced by volcanic -associated hydrothermal events in submarine environments. [ 2][ 3][ 4] These deposits are also sometimes called volcanic-hosted massive sulfide (VHMS) deposits.
Uranium ore (pitchblende in dolomite) from the vein-type deposit Niederschlema-Alberoda Polymetallic uranium ore, Marienberg, Erzgebirge Mountains, Germany. Vein deposits play a special role in the history of uranium: the term "pitchblende" ("pechblende") originates from German vein deposits when they were mined for silver in the 16th century.
Caliche fossil forest on San Miguel Island, California. Caliche (/ k ə ˈ l iː tʃ iː /) - (unrelated to the street-slang "Caliche" spoken in El Salvador) - is a sedimentary rock, a hardened natural cement of calcium carbonate that binds other materials—such as gravel, sand, clay, and silt.
Bright spots on Ceres. Several bright surface features (also known as faculae) were discovered on the dwarf planet Ceres by the Dawn spacecraft in 2015. The brightest cluster of spots ("Spot 5") is located in an 80-kilometer (50 mi) crater called Occator. [ 1][ 2] The largest and brightest component of the cluster is in the center of the crater ...
Komatiite. Komatiite / koʊˈmɑːtiˌaɪt / is a type of ultramafic mantle -derived volcanic rock defined as having crystallised from a lava of at least 18 wt% magnesium oxide (MgO). [1] It is classified as a 'picritic rock'. Komatiites have low silicon, potassium and aluminium, and high to extremely high magnesium content.