Dickinsonite-(KMnNa) is a rare secondary phosphate mineral typically found in complex granite pegmatites. Collectors look for its characteristic olive-green, platy, or foliated habits that often form in cavities alongside other secondary phosphates.

Hardness

3.5-4

Mohs

Luster

Vitreous

Streak

White

Transparency

Translucent

mineralrareDickinsonite Group family

Dickinsonite-(KMnNa)

Hardness: 3.5-4
Luster: Vitreous
Streak: White
Transparency: Translucent

No image

Is this dickinsonite-(kmnna)?

5-step field check

Run through these checks against the specimen in your hand. The more boxes tick, the more confident the ID.

1
Test the hardness
Try to scratch dickinsonite-(kmnna) with a known reference. Dickinsonite-(KMnNa) sits at Mohs 3.5-4 — softer than the next harder reference, harder than the previous one.
2
Check the streak
Drag the specimen across an unglazed porcelain plate. Dickinsonite-(KMnNa) leaves a white streak.
3
Read the luster
Hold the specimen under a strong light. Dickinsonite-(KMnNa) typically shows a vitreous luster.
4
Match the color range
Compare against the expected color range: olive-green, yellow-green, brownish-green.
5
Look at form & habit
Crystal system: monoclinic. Typical habit: tabular crystals, foliated masses, lamellar aggregates.

Often confused with

Dickinsonite-(KMnNa) vs. its common look-alikes — and how to tell them apart in the field.

Often found alongside dickinsonite-(kmnna)

Minerals reported to co-occur with dickinsonite-(kmnna). Spotting these in float or country rock is a strong cue you are in the right ground.

All properties

Chemical formula: KNa₄Mn₁₄Al(PO₄)₁₂(OH)₂
Mohs hardness: 3.5-4
Density: 3.4 g/cm³
Colors: Olive-green Yellow-green Brownish-green
Streak: White
Luster: Vitreous
Transparency: Translucent
Crystal system: Monoclinic
Crystal habit: Tabular Crystals, Foliated Masses, Lamellar Aggregates
Cleavage: Perfect Basal
Rarity: Rare
Uses: Collector
Host rock: Granite Pegmatites
Typical price: $20-150 thumbnail, $200+ cabinet specimen

Where rockhounds find dickinsonite-(kmnna)

Classic worldwide localities

Branchville, Connecticut, USA
Poland, Maine, USA
Hagendorf, Bavaria, Germany
Tip Top mine, South Dakota, USA

Field-hunting tip

Look in granite pegmatites country — that is the host setting where dickinsonite-(kmnna) typically forms. If you start seeing eosphorite, triphylite, apatite in float, you are in the right ground. Field specimens usually show a tabular crystals, foliated masses, lamellar aggregates habit, so train your eye for that shape before scanning the outcrop.

Common questions

How do you identify dickinsonite-(kmnna)?+

Mohs hardness is 3.5-4. It typically shows a vitreous luster. The streak is white. Common colors include olive-green, yellow-green, brownish-green.

Where is dickinsonite-(kmnna) found?+

Notable localities include Branchville, Connecticut, USA; Poland, Maine, USA; Hagendorf, Bavaria, Germany; Tip Top mine, South Dakota, USA.

How much is dickinsonite-(kmnna) worth?+

Typical asking prices fall in the range of $20-150 thumbnail, $200+ cabinet specimen. Quality, size, and provenance can move individual specimens well outside that range.

What rocks look like dickinsonite-(kmnna)?+

Dickinsonite-(KMnNa) is most often confused with Fairfieldite, Fillowite. A quick hardness test and a streak check separate the look-alikes faster than color alone.

What minerals are found with dickinsonite-(kmnna)?+

Dickinsonite-(KMnNa) commonly co-occurs with Eosphorite, Triphylite, Apatite, Albite. Spotting any of these in float or country rock is a useful trip signal.

What kind of rock does dickinsonite-(kmnna) form in?+

Dickinsonite-(KMnNa) typically forms in granite pegmatites. Working float back to the host body is the standard way to chase a fresh occurrence.

What is dickinsonite-(kmnna) used for?+

Dickinsonite-(KMnNa) is used in collector.

Find dickinsonite-(kmnna) on the map

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