Vivianite


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vivianite

[′vi·vē·ə‚nīt]
(mineralogy)
Fe3(PO4)2·8H2O A colorless, blue, or green mineral in the unaltered state (darkens upon oxidation); crystallizes in the monoclinic system and occurs in earth form and as globular and encrusting fibrous masses. Also known as blue iron earth; blue ocher.

Vivianite

 

(named in 1817 after the English mineralogist J. G. Vivian), a mineral, a hydrous ferrous phosphate: Fe3(PO4)2’ 8H2O. It crystallizes in a monoclinic system and occurs in powdery or dense masses. Vivianite has a hardness of 1.5-2.0 on the mineralogical scale, a density of 2,680-2,710 kg/m3, and a pale green color that turns blue in air. Formed by exogenous processes, it is widespread in peat bogs and in sedimentary iron ore deposits that are rich in phosphorus. The mineral is used as a phosphorus fertilizer and in making dark blue paint.

References in periodicals archive ?
Vivianite is a widespread mineral in lacustrine sediments (see samples of world occurrences in Fagel et al.
However, with the passage of time, the remaining "cornflower blue" mineral inclusions also found in these units, which may be vivianite crystals, retained their coloration and, if anything, had only deepened in color.
Herein we report the discovery of a new location of the mineral vivianite and the research conducted to determine why it occurs in an unusual place, a creek within the city limits of Memphis, Tennessee.
Thin section and scanning electron microscope images reveal that these cleavages are defined by microveins of calcite, gypsum, and montmorillonitic clays with hematite and vivianite, and that there is some evidence for silica dissolution.
Vivianite, which is only persistent under the absence or lack of oxygen, was found in the subsoil of a Haplocryod on an abandoned penguin rookery (Blume et al.
The place in question is an entirely landlocked, mountainous, somewhat mysterious-seeming country which boasts a long mining history and has a secure reputation for turning out world-class specimens of--oh, let's see--metallic species (andorite, pyrarygrite, stannite, franckeite, cylindrite), other primary ores (cassiterite, ferberite), and glamorous phosphates (phosphophyl-lite, paravauxite, vivianite, ludlamite) such as we have long admired and lusted after.
Because erythrite forms thin, leafy crystals and is very soft and non-elastic (like vivianite and gypsum), it is difficult to collect and transport without damage.
Minerals that have reached the specimen market include countless thousands of fine specimens of sulfides such as pyrrhotite, arsenopyrite, sphalerite and galena, associated with well-crystallized quartz, dolomite, vivianite, ludlamite, calcite and rhodochrosite.
Cornish vivianite crystals, 3 inches; Rutile and emerald crystals from Alexander County, North Carolina.
Pearly white to capucine-orange mammillary masses of resinous, amorphous allophane form the matrix in some vauxite, vivianite and wavellite specimens.
The locality is the Canutillos lead-silver mine in Potosi department (the mine near whose portal moonlighting miners have lately been finding wonderful vivianite specimens in outcrops of muddy red sandstone--see my Denver 2004 report).