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 — Ercitite leaves yellowish-white, Variscite leaves white; luster reads vitreous on Ercitite and waxy on Variscite.
How to tell apart: Streak differs — 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 — that is 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.
