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Lepidocrocite (γ-FeO(OH)), also called esmeraldite or hydrohematite, is an iron oxide-hydroxide mineral. Lepidocrocite has an orthorhombic crystal structure, a hardness of 5, specific gravity of 4, a submetallic luster and a yellow-brown streak. It is red to reddish brown and forms when iron-containing substances rust underwater.
The minerals within this soil are goethite, lepidocrocite, and hematite. [22] In recognition of the weathering process that these minerals require, they are classified as rare earth minerals. [23] In addition to these rare minerals other elements are contained within this soil like substance such as iron and nickel. [24]
Maghemite can also form through dehydration and transformation of certain iron oxyhydroxide minerals, such as lepidocrocite and ferrihydrite. It occurs as widespread brown or yellow pigment in terrestrial sediments and soils. It is associated with magnetite, ilmenite, anatase, pyrite, marcasite, lepidocrocite and goethite. [3]
Unusual specimen of goethite replacing a gypsum stalactite; the center is hollow.From Santa Eulalia, Chihuahua, Mexico.. Goethite (/ ˈ ɡ ɜːr t aɪ t /, [6] [7] US also / ˈ ɡ oʊ θ aɪ t / [8] [9]) is a mineral of the diaspore group, consisting of iron(III) oxide-hydroxide, specifically the α-polymorph.
This process has been conjectured to occur in soil solutions and aquifers. [19] In one experiment, a 160 mM suspension of orange lepidocrocite γ-FeOOH in a solution containing formate (HCO − 2), incubated for 3 days with a culture of Shewanella putrefaciens, turned dark green due to the conversion of the hydroxide to GR(CO 2−
The first comprehensive review on the subject was published in 2017 by the chemist and soil scientist Timothy A Doane, [1] but the term photogeochemistry appeared a few years earlier as a keyword in studies that described the role of light-induced mineral transformations in shaping the biogeochemistry of Earth; [2] this indeed describes the ...
Lepidocrocite, the γ polymorph, is commonly encountered as rust on the inside of steel water pipes and tanks. Feroxyhyte (δ) is formed under the high pressure conditions of sea and ocean floors, being thermodynamically unstable with respect to the α polymorph (goethite) at surface conditions.
Amethyst crystals – a purple quartz Apophyllite crystals sitting right beside a cluster of peachy bowtie stilbite Aquamarine variety of beryl with tourmaline on orthoclase Arsenopyrite from Hidalgo del Parral, Chihuahua, Mexico Aurichalcite needles spraying out within a protected pocket lined by bladed calcite crystals Austinite from the Ojuela Mine, Mapimí, Durango, Mexico Ametrine ...