Ercitite is an extremely rare phosphate mineral discovered in complex granite pegmatites. It typically appears as small, thin, tabular crystals or radiating aggregates of yellow to brownish-yellow color often found associated with other secondary phosphate minerals.
Is this ercitite?
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 ercitite with a known reference. Ercitite sits at Mohs 3.5, softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Ercitite leaves a yellowish-white streak.
- 3Read the lusterHold the specimen under a strong light. Ercitite typically shows a vitreous luster.
- 4Match the color rangeCompare against the expected color range: yellow, brownish-yellow.
- 5Look at form & habitCrystal system: monoclinic. Typical habit: tabular crystals, radiating aggregates.
Often confused with
Ercitite vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Streak differs, so Ercitite leaves yellowish-white, Variscite leaves white; luster reads vitreous on Ercitite and waxy on Variscite.
How to tell apart: Streak differs, so Ercitite leaves yellowish-white, Strengite leaves white.
Often found alongside ercitite
Minerals reported to co-occur with ercitite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- NaMn³⁺(PO₄)(OH)·2H₂O
- Mohs hardness
- 3.5
- Density
- 2.81 g/cm³
- Colors
- Streak
- Yellowish-white
- Luster
- Vitreous
- Transparency
- Transparent
- Crystal system
- Monoclinic
- Crystal habit
- Tabular Crystals, Radiating Aggregates
- Cleavage
- Perfect
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Granite Pegmatites
- Typical price
- $50-300 per specimen
Where rockhounds find ercitite
Classic worldwide localities
- Mangualde, Portugal
- Sapucaia pegmatite, Brazil
Field-hunting tip
Look in granite pegmatites country, the host setting where ercitite typically forms. If you start seeing triplite, phosphosiderite, apatite in float, you are in the right ground. Field specimens usually show a tabular crystals, radiating aggregates habit, so train your eye for that shape before scanning the outcrop.
Common questions
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Find ercitite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
