THE MINERAL VIVIANITE
- Chemistry: Fe3(PO4)2-(H2O)8, Hydrated Iron Phosphate
- Class: Phosphates
- Group: Vivianite
- Uses: only as a mineral specimen
Vivianite has vibrant colors and a nice sparkle.
Many clusters are found inside of fossil clam or snail shells or attached to fossil animal bone.
Vivianite is not a display case type mineral.
Specimens should be kept from long exposure to light as this can darken a specimen to near blackness.
The reason for the darkening is from the oxidation of the iron from +2 to +3 and this change yeilds a darker specimen.
The oxidation is accelerated by exposure to light.
Vivianite can be enjoyed and then should be put back in a dark cabinet to preserve its beauty for years to come.
- Color is blue, green and colorless, darkens upon exposure to light.
- Luster is vitreous.
- Transparency crystals are transparent to translucent.
- Crystal System is monoclinic; 2/m
- Crystal Habits include radiating clusters of prismatic, acicular, or fiberous crystals.
Also earthy and encrusting masses.
Often lines the inside of fossil shells.
- Cleavage is perfect in one direction.
- Fracture is splintery.
- Hardness is 1.5 - 2.
- Specific Gravity is approximately 2.6+ (average for translucent minerals)
- Streak is white or bluish green.
- Associated Minerals are siderite, sphalerite, quartz and some secondary ore deposit minerals.
- Other Characteristics: thin crystals are flexible.
- Notable Occurances include Maryland and Colorado, USA; Russia; Ukraine and England.
- Best Field Indicators are color and reaction to light, flexible crystals and crystal habit.