Triploidite
A variety of Minerals

What is Triploidite?
Triploidite is an uncommon manganese iron phosphate mineral with formula: (Mn,Fe)2PO4OH. It crystallizes in the monoclinic crystal system and typically occurs as elongated and striated slender prisms which may be columnar to fibrous. Its crystals may be pinkish to yellowish brown or red-orange. It was first described in 1878 for an occurrence in the Branchville Quarry, Branchville, Fairfield County, Connecticut. The name is derived from its resemblance to triplite. It typically occurs as a hydrothermal alteration product of primary phosphate minerals in granite pegmatites. It occurs with triplite, lithiophilite, triphylite, eosphorite, dickinsonite and rhodochrosite. It forms a solid solution series with the iron rich wolfeite.
Market Value Factors
Pricing varies for every rock and mineral, so use these universal factors to gauge Triploidite before comparing listings or appraisals.
Size & Weight
Larger, intact specimens usually command higher prices.
Rarity & Demand
Scarce material or popular varieties sell at a premium.
Condition & Finish
Chips, repairs, and heavy wear lower value; clean prep helps.
Treatment & Provenance
Untreated specimens with documented locality are prized.
Triploidite Localities Map
See where Triploidite is found with a localities map, collecting zones, and geology context. Generate a sample map preview below.
Quick Facts
Physical Properties
- Color
- Red-brown, light pink, yellow-brown; light pink to light brown in transmitted light.
- Hardness (Mohs)
- 4.5 - 5
- Density
- 3.8 g/cm³
- Streak
- White, off-white.
Chemical Properties
- Chemical Formula
- Mn2+2(PO4)(OH)
- Elements
- H, Mn, O, P

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Triploidite FAQs
How do I identify Triploidite?
Triploidite can be identified by its hardness of 4.5 - 5 on the Mohs scale, Red-brown color. Look for these key characteristics when examining specimens.
What color is Triploidite?
Triploidite typically appears in Red-brown, light pink, yellow-brown; light pink to light brown in transmitted light.. Color can vary depending on impurities and formation conditions.
How hard is Triploidite?
Triploidite has a hardness of 4.5 - 5 on the Mohs scale. This gives it moderate hardness.


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