Vivianite

Vivianite is the iconic deep-blue iron phosphate, prized for its translucent indigo crystals. The Yongping copper mine in Jiangxi has produced the world's finest vivianite specimens – deep blue, often gemmy, in clay matrix.

Key Facts

• Mohs hardness 1.5-2 – softer than fingernail; extremely fragile.
• Color darkens with light exposure due to Fe2+ to Fe3+ oxidation. Store in dark.
• Forms in iron-phosphate-rich reducing environments – bogs, fossil bones, copper mines.
• Yongping (Jiangxi) yields some of the world's best gem-grade specimens.
• Easily cleaves on {010} – handle by matrix only, never by the crystal.

The Chinese Angle

The Yongping Mine in Jiangxi has produced a sustained run of world-class vivianite – indigo-blue prismatic crystals up to 10 cm, perched on or partially embedded in clay-altered matrix, often with pyrrhotite or sphalerite. These have set the modern reference for gem-grade vivianite.