Overite is a scarce phosphate mineral that typically forms as delicate, colorless to pale yellow blades or radial clusters. It is highly sought after by micromount collectors and is famously associated with the phosphate nodules found in the Fairfield vivianite locality of Utah.
Is this overite?
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 overite with a known reference. Overite sits at Mohs 4 — softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Overite leaves a white streak.
- 3Read the lusterHold the specimen under a strong light. Overite typically shows a vitreous luster.
- 4Match the color rangeCompare against the expected color range: colorless, white, pale yellow, greenish.
- 5Look at form & habitCrystal system: orthorhombic. Typical habit: bladed crystals, radial aggregates, crusts.
Often confused with
Overite vs. its common look-alikes — and how to tell them apart in the field.
How to tell apart: Overite is noticeably harder (Mohs 4 vs. 3).
How to tell apart: Luster reads vitreous on Overite and waxy on Variscite.
How to tell apart: Crandallite is the harder of the two (Mohs 5 vs. 4).
Often found alongside overite
Minerals reported to co-occur with overite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- CaMgAl(PO₄)₂(OH)₂·4H₂O
- Mohs hardness
- 4
- Density
- 2.51 g/cm³
- Streak
- White
- Luster
- Vitreous
- Transparency
- Transparent
- Crystal system
- Orthorhombic
- Crystal habit
- Bladed Crystals, Radial Aggregates, Crusts
- Cleavage
- Perfect On {010}
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Phosphate Nodules in Shales and Metamorphic Rocks
- Typical price
- $20-200 per specimen depending on size and association
Where rockhounds find overite
Classic worldwide localities
- Fairfield, Utah, USA
- Cabrerets, France
- Plešovice, Czech Republic
Field-hunting tip
Look in phosphate nodules in shales and metamorphic rocks country — that is the host setting where overite typically forms. If you start seeing montgomeryite, wardite, variscite in float, you are in the right ground. Field specimens usually show a bladed crystals, radial aggregates, crusts habit, so train your eye for that shape before scanning the outcrop.
Common questions
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Find overite on the map
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