Gayite is a rare phosphate mineral typically found as small, fibrous radial clusters in complex granite pegmatites. Collectors generally search for it in association with secondary phosphate minerals in the inner zones of zoned pegmatites.
Is this gayite?
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 gayite with a known reference. Gayite 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. Gayite leaves a olive green streak.
- 3Read the lusterHold the specimen under a strong light. Gayite typically shows a vitreous luster.
- 4Match the color rangeCompare against the expected color range: greenish black.
- 5Look at form & habitCrystal system: monoclinic. Typical habit: fibrous radial aggregates, encrustations.
Often confused with
Gayite vs. its common look-alikes, and how to tell them apart in the field.
Often found alongside gayite
Minerals reported to co-occur with gayite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- NaMnFe₃(PO₄)₃(OH)₂
- Mohs hardness
- 4
- Density
- 3.15 g/cm³
- Colors
- Streak
- Olive Green
- Luster
- Vitreous
- Transparency
- Transparent
- Crystal system
- Monoclinic
- Crystal habit
- Fibrous Radial Aggregates, Encrustations
- Cleavage
- Good
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Granite Pegmatites
Where rockhounds find gayite
Classic worldwide localities
- Tip Top mine, South Dakota, USA
- Hagendorf-Pleystein, Bavaria, Germany
- Mangualde, Portugal
Field-hunting tip
Look in granite pegmatites country, the host setting where gayite typically forms. If you start seeing triphylite, fairfieldite, eosphorite in float, you are in the right ground. Field specimens usually show a fibrous radial aggregates, encrustations habit, so train your eye for that shape before scanning the outcrop.
Common questions
How do you identify gayite?+
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Find gayite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
