Vivianite is a hydrated iron phosphate mineral prized for its stunning, deep blue to green prismatic crystals. It is famously light-sensitive; freshly mined crystals may appear colorless or pale, but they darken rapidly when exposed to light, so specimens should be stored in the dark.
Is this vivianite?
5-step field checkRun through these checks against the specimen in your hand. The more boxes tick, the more confident the ID.
- 1Test the hardnessTry to scratch vivianite with a known reference. Vivianite sits at Mohs 1.5-2 — softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Vivianite leaves a white to light blue streak.
- 3Read the lusterHold the specimen under a strong light. Vivianite typically shows a vitreous luster.
- 4Match the color rangeCompare against the expected color range: colorless, white, pale green, dark blue, deep blue-green, indigo.
- 5Look at form & habitCrystal system: monoclinic. Typical habit: prismatic to acicular crystals, often as radial aggregates or earthy masses.
Often confused with
Vivianite vs. its common look-alikes — and how to tell them apart in the field.
How to tell apart: Ludlamite is the harder of the two (Mohs 3.5 vs. 1.5-2); streak differs — Vivianite leaves white to light blue, Ludlamite leaves white.
How to tell apart: Kurnakovite is the harder of the two (Mohs 3 vs. 1.5-2); streak differs — Vivianite leaves white to light blue, Kurnakovite leaves white.
Often found alongside vivianite
Minerals reported to co-occur with vivianite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Fe₃(PO₄)₂·8H₂O
- Mohs hardness
- 1.5-2
- Density
- 2.68 g/cm³
- Streak
- White to Light Blue
- Luster
- Vitreous
- Transparency
- Transparent
- Crystal system
- Monoclinic
- Crystal habit
- Prismatic to Acicular Crystals, Often as Radial Aggregates or Earthy Masses
- Cleavage
- Perfect On {010}
- Rarity
- Common
- Uses
- Collector, Mineral Specimen
- Host rock
- Sedimentary Iron Ore Deposits and Hydrothermal Veins
- Typical price
- $10-100 thumbnail, $50-500 cabinet specimen
Where rockhounds find vivianite
6 mapped spotsClassic worldwide localities
- Kerch Peninsula, Ukraine
- Blackbird Mine, Idaho, USA
- Ashio Mine, Japan
- Cornwall, England
- Llallagua, Bolivia
Field-hunting tip
Look in sedimentary iron ore deposits and hydrothermal veins country — that is the host setting where vivianite typically forms. If you start seeing siderite, pyrite, limonite in float, you are in the right ground. Field specimens usually show a prismatic to acicular crystals, often as radial aggregates or earthy masses habit, so train your eye for that shape before scanning the outcrop. In the U.S., the densest reported localities are in Missouri, Alabama, Florida — start trip planning there.
Common questions
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Find vivianite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
