Mineral
Vivianite
Fe₃(PO₄)₂·8H₂OVivianit
A very soft iron phosphate, colourless when fresh and turning from blue to black in light and air; a mineral of bogs and peat sediments.
- Popularly: Common stone
In short
Vivianite is a mineral made of iron, phosphorus, oxygen and water (iron phosphate octahydrate, Fe₃(PO₄)₂·8H₂O). Freshly exposed it is colourless or very pale green; in air and light its iron oxidises and it turns dark blue, greenish blue and finally almost black. It is very soft, and its thin plates are flexible and can be cut with a knife. It forms in bog and lake sediments, in peat, in some fossil bones, and in the weathered zones of ore deposits. Its name is generally taken to honour John Henry Vivian (1785–1855), a mine owner from Cornwall.
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How does it form?
Vivianite forms in phosphate-rich settings with little oxygen, where iron stays in its two-valent form (Fe²⁺): in bog and lake sediments, in peat and in bog-iron ores. It also appears in fossil bones and teeth, taking the place of decaying organic matter; bones and teeth buried in peat bogs have sometimes been replaced by vivianite. It is also found in the weathered zones near the surface of ore deposits and in complex granite pegmatites, and rarely in caves. Once brought out into light and air its iron oxidises and it changes colour; in the end vivianite can turn into a yellow-brown mineral called metavivianite.
What is it used for?
- Pigment: It has been used since Roman times to make paint, under the name “blue ochre”. But its tendency to fade, and to oxidise in air to yellow-brown, is a problem for painting conservators.
- Collecting: Its blue-green, lustrous and sometimes very large crystals are favourites of mineral collectors; specimens need to be kept away from light.
- Jewellery: Being very soft, flexible and sensitive to light, it is only rarely cut and is not suited to everyday jewellery.
- Science: Its possible presence on Mars interests astrobiologists because it could be a biosignature.
What determines its value?
Vivianite is not an industrial ore or a jewellery stone; its value is as a collector’s specimen. Collectors look for large, lustrous, well-formed and undamaged crystals, a vivid blue-green colour, and specimens from famous places such as Bolivia or Cameroon. Because it is very soft and sensitive to light, to protect their colour, specimens are best kept away from light, in the dark.
This information is educational, not buying, selling or investment advice. Value varies enormously with quality and treatment.
How to recognise it
- 1
It is very soft (hardness 1.5–2): a fingernail scratches it; thin plates are flexible and can be cut with a knife.
- 2
Its colour is the key clue: colourless or very pale green on a fresh break, turning blue, greenish blue and finally black on exposure to light and air in a short time (within minutes in some specimens).
- 3
Its streak is white, but it turns dark blue or brown in contact with air.
- 4
The perfect cleavage surface has a pearly shine, other surfaces are glassy, and earthy specimens are dull.
- 5
Seen from different angles it shows different colours (pleochroism): shades of blue, yellowish green and olive-yellow.
Fakes and imitations
What shops usually don’t tell you:
- Blue fossil bone and ivory is known as “odontolite” or “bone turquoise”; its colour is traditionally thought to come from phosphate minerals such as turquoise or vivianite. It is a fossil coloured by vivianite, not vivianite itself.
Myths and misconceptions
MythVivianite is naturally a blue stone.
FactFreshly broken vivianite is colourless or very pale green. The blue, greenish-blue and black colours develop afterwards, as the iron in it is oxidised by air and light.
MythBlue vivianite is a jewellery stone you can wear safely, like turquoise.
FactVivianite is not related to turquoise (it is an iron phosphate) and it is very soft (1.5–2), flexible and sensitive to light; it is rarely cut and is seen in collections far more often than in jewellery.
Did you know?
Vivianite crystals can grow to 1.3 m; crystals over a metre long found in mud in Cameroon are regarded as the largest vivianite crystals in the world.
Vivianite has been used since Roman times as a pigment called “blue ochre”; it has been identified in paintings by Dutch Golden Age artists, for example Vermeer’s “The Procuress” and Rembrandt’s “Susanna” (1636).
A paper published in Nature in September 2025 reported the “likely” detection of vivianite and greigite in Jezero crater on Mars by the Perseverance rover; the pairing is being discussed as a possible biosignature of iron-oxidising life.
Where is it found?
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- Wheal Kind, St Agnes, Cornwall, England · Type localityThe type locality according to Wikipedia: Wheal Kind in the West Wheal Kitty group of mines; the Handbook of Mineralogy also lists the St Agnes mines of Cornwall
- Llallagua, Potosí, Bolivia · Major depositA tin-mining district listed by the Handbook of Mineralogy for exceptional Bolivian specimens; according to Wikipedia, the Siglo XX mine has produced crystals up to 10 cm
- Anloua area, near Ngaoundéré, Adamawa Region, Cameroon · Major depositHome of the crystals over a metre long found in mud, regarded as the largest vivianite crystals in the world
- Kerch area, Crimean Peninsula, Ukraine · Known localityA peninsula known for its iron-ore deposits, listed by the Handbook of Mineralogy for vivianite
- Ashio mine, Tochigi Prefecture, Japan · Known localityAn old copper mine, closed in 1973, listed by the Handbook of Mineralogy for vivianite
- Leadville, Colorado, USA · Known localityAn old silver–lead mining town with the Treece and Ibex mines, listed by the Handbook of Mineralogy for vivianite
Locations are approximate to protect sites. Red dots mark places in Türkiye. Open in the big map →
Frequently asked questions
What is vivianite?
Vivianite is a mineral made of iron, phosphorus, oxygen and water (iron phosphate octahydrate, Fe₃(PO₄)₂·8H₂O). Freshly exposed it is colourless or very pale green; in air and light its iron oxidises and it turns dark blue, greenish blue and finally almost black. It is very soft, and its thin plates are flexible and can be cut with a knife. It forms in bog and lake sediments, in peat, in some fossil bones, and in the weathered zones of ore deposits. Its name is generally taken to honour John Henry Vivian (1785–1855), a mine owner from Cornwall.
What is vivianite used for?
Pigment: It has been used since Roman times to make paint, under the name “blue ochre”. But its tendency to fade, and to oxidise in air to yellow-brown, is a problem for painting conservators. Collecting: Its blue-green, lustrous and sometimes very large crystals are favourites of mineral collectors; specimens need to be kept away from light. Jewellery: Being very soft, flexible and sensitive to light, it is only rarely cut and is not suited to everyday jewellery. Science: Its possible presence on Mars interests astrobiologists because it could be a biosignature.
How hard is vivianite?
It has a hardness of 1.5–2 on the Mohs scale. It is soft enough to scratch with a fingernail. Its specific gravity is 2.68–2.69 g/cm³.
Where is vivianite found?
Its best-known localities: Wheal Kind, St Agnes, Cornwall, England; Llallagua, Potosí, Bolivia; Anloua area, near Ngaoundéré, Adamawa Region, Cameroon; Kerch area, Crimean Peninsula, Ukraine; Ashio mine, Tochigi Prefecture, Japan.
How can you tell if vivianite is real?
It is very soft (hardness 1.5–2): a fingernail scratches it; thin plates are flexible and can be cut with a knife. Its colour is the key clue: colourless or very pale green on a fresh break, turning blue, greenish blue and finally black on exposure to light and air in a short time (within minutes in some specimens). Its streak is white, but it turns dark blue or brown in contact with air. Blue fossil bone and ivory is known as “odontolite” or “bone turquoise”; its colour is traditionally thought to come from phosphate minerals such as turquoise or vivianite. It is a fossil coloured by vivianite, not vivianite itself.
Is vivianite valuable?
On the “street to diamond” value ladder it sits on step 4 of nine: Fine dimension stone and ore. Vivianite is not an industrial ore or a jewellery stone; its value is as a collector’s specimen. Collectors look for large, lustrous, well-formed and undamaged crystals, a vivid blue-green colour, and specimens from famous places such as Bolivia or Cameroon. Because it is very soft and sensitive to light, to protect their colour, specimens are best kept away from light, in the dark.
Sources
- Vivianite · Wikipedia
- Handbook of Mineralogy: Vivianite · Mineralogical Society of America
- Vivianite · Encyclopaedia Britannica
- Vivianite · Webmineral
- Odontolite · Wikipedia
- Vivianite · Gem Society
- Ashio Copper Mine · Wikipedia
External links
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