(n.) A hydrous oxide of iron, occurring in prismatic crystals, also massive, with a fibrous, reniform, or stalactitic structure. The color varies from yellowish to blackish brown.
Example Sentences:
(1) This can be understood in terms of the microcrystalline goethite structure of the cores as indicated by electron diffraction.
(2) The thermodynamic stabilities of ferric oxyhydroxides, as described by the activity product in solution pK = -log [Fe(3+)] [OH(-)](3) range from pK = 37.1 for freshly precipitated amorphous oxyhydroxide to pK = 44.2 for well crystallized goethite.
(3) The activity profiles, were also found to vary with ionic strength, the pH at which enzyme adsorbed onto the mineral surface, and in the case of goethite, on the nature of the anions in the buffer.
(4) Opal and goethite mineralize the cusps and bases of the teeth.
(5) Different pH profiles of activity profiles were found when the enzyme was adsorbed onto montmorillonite, kaolinite and goethite.
(6) This could be linked to the presence of ferrous ions in this solid iron oxide, since the ferric oxides haematite and goethite are completely inactive.
(7) Haemosiderin iron cores isolated from patients with secondary haemochromatosis have a goethite-like (alpha-FeOOH) crystal structure whereas those from patients with primary haemochromatosis are amorphous Fe (III) oxide.
Limonite
Definition:
(n.) Hydrous sesquioxide of iron, an important ore of iron, occurring in stalactitic, mammillary, or earthy forms, of a dark brown color, and yellowish brown powder. It includes bog iron. Also called brown hematite.
Example Sentences:
(1) Reactions between the mineral limonite and hydrogen peroxide were studied and gases produced thereupon were analysed by gas chromatography.
(2) Yellow iron oxide, also known as limonite or yellow ochre, is a common cosmetic dye which has not previously been described as a source of contact dermatitis.
(3) A mixture of carbon dioxide and carbon monoxide was irradiated in the presence of limonite and hydrogen peroxide at 340 nm.
(4) Oxygen did not evolve if limonite was added to hydrogen peroxide frozen at a temperature of dry ice.
(5) The effect of hydrogen peroxide and the mineral limonite on the rate of microbial processes was studied in poor and rich soils.
(6) Limonite stimulates the metabolic activity of microrganisms.
(7) This work supports the conclusion that, theoretically, the ground of Mars may contain microorganisms which have adapted, in the course of evolution, to high concentrations of hydrogen peroxide and hydrated iron oxides (of the limonite type) in the surrounding medium.
(8) The result indicates that the domestic commercial traditional medicine Wumingyi is practically limonite, therefore further investigations should be made to find out the correct mineral sources.
(9) The cultural and morphological properties of microflora are described, which are typical of soils incubated in the presence of limonite and hydrogen peroxide.