Vivianite


Vivianite is a popular mineral composed of iron phosphate. [1]

Images of vivianite

Vivianite: Quick Facts and Characteristics

Some quick facts for Vivianite:
  • Transparency: Vivianite can be opaque, translucent or transparent.
  • Crystallography: In terms of crystallography, vivianite is monoclinic.
  • Luster: In terms of luster, vivianite can be dull, pearly or vitreous (glassy).
  • Streak: Vivianite streaks blue, exposure, greenish-blue, greenish-blue blue, turns greenish-blue, white or white; turns.
  • Hardness: Vivianite's hardness ranges from 1.5 to 2 on the Moh's scale.
  • Specific Gravity: Vivianite's specific gravity ranges from 2.64 to 2.68.

Vivianite: Background and Summary

Vivianite is a rare mineral that has a blue-green color and is found in iron-rich environments. It is a hydrated iron phosphate that often forms as a secondary mineral in organic-rich sedimentary rocks. The mineral is named after the British mineralogist John Henry Vivian, who first described it in 1817.

Vivianite is typically found in small crystals or as a coating on other minerals. It has a hardness of 1.5-2 on the Mohs scale and a specific gravity of 2.7-2.9. The color of vivianite can vary from pale blue to dark green, depending on the amount of iron present in the crystal lattice. One way to identify vivianite is by its characteristic blue-green color and its tendency to form as small, elongated crystals.

Despite its rarity, vivianite has several practical uses. It is sometimes used as a pigment in ceramics and paints due to its blue-green color. Additionally, vivianite has been used in the past as a fertilizer due to its high phosphorus content. However, its use as a fertilizer is limited due to the fact that it breaks down quickly in soil and can release toxic levels of iron.

Vivianite: Table of Properties

Attribute Vivianite (src)
Transparency transparent, translucent, opaque
Chemical Formula Fe3(PO4)2· 8(H2O)
Chemical Composition iron phosphate
Specific Gravity 2.64, 2.68
Hardness 1.5, 2
Streak white; turns, white, blue, turns greenish-blue, greenish-blue blue, exposure, greenish-blue
Crystallography monoclinic
Refractive Index 1.569, 1.675
Hydrous Yes
Colors common: blue, green, purple
sometimes: black
less common: pale, colorless, multicolor
Solubility Soluble in acids
Category phosphate
Birefringence δ = 0.050–0.059


Vivianite: FAQ

Q: Is vivianite toxic?
A: Vivianite itself is not toxic, but it can release toxic levels of iron if used as a fertilizer.

Q: Where is vivianite found?
A: Vivianite is found in iron-rich environments, typically as a secondary mineral in organic-rich sedimentary rocks.

Q: What is the hardness of vivianite?
A: Vivianite has a hardness of 1.5-2 on the Mohs scale.

Sources

- "Vivianite." Mindat.org. https://www.mindat.org/min-4219.html
-
"Vivianite Mineral Data." Webmineral.com. https://www.webmineral.com/data/Vivianite.shtml
- Vivianite: https://en.wikipedia.org/wiki/Vivianite

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