Triploidite is an uncommon phosphate mineral typically found in phosphate-rich zones of complex granite pegmatites. Collectors look for its characteristic yellow-to-brownish massive aggregates or small, somewhat fibrous prismatic crystals often associated with other rare phosphate species.
Is this triploidite?
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 triploidite with a known reference. Triploidite sits at Mohs 4.5-5, softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Triploidite leaves a white streak.
- 3Read the lusterHold the specimen under a strong light. Triploidite typically shows a vitreous luster.
- 4Match the color rangeCompare against the expected color range: yellow, yellow-brown, pink, reddish-brown.
- 5Look at form & habitCrystal system: monoclinic. Typical habit: fibrous, massive, or as prismatic crystals.
Often confused with
Triploidite vs. its common look-alikes, and how to tell them apart in the field.
Often found alongside triploidite
Minerals reported to co-occur with triploidite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- (Mn,Fe)₂PO₄(OH)
- Mohs hardness
- 4.5-5
- Density
- 3.7-3.9 g/cm³
- Streak
- White
- Luster
- Vitreous
- Transparency
- Translucent
- Crystal system
- Monoclinic
- Crystal habit
- Fibrous, Massive, Or as Prismatic Crystals
- Cleavage
- Distinct
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Granite Pegmatites
- Typical price
- $20-150 for thumbnail to small cabinet specimens
Where rockhounds find triploidite
Classic worldwide localities
- Branchville, Connecticut, USA
- Mangualde, Portugal
- Hagendorf, Germany
- Minas Gerais, Brazil
Field-hunting tip
Look in granite pegmatites country, the host setting where triploidite typically forms. If you start seeing eosphorite, dickinsonite, apatite in float, you are in the right ground. Field specimens usually show a fibrous, massive, or as prismatic crystals habit, so train your eye for that shape before scanning the outcrop.
Common questions
How do you identify triploidite?+
Where is triploidite found?+
How much is triploidite worth?+
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What minerals are found with triploidite?+
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Find triploidite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
