Arrojadite-(KNa) is a complex phosphate mineral typically found as massive or granular aggregates within phosphate-rich granite pegmatites. It is often identified by its characteristic greenish-brown color and its association with other primary and secondary phosphate minerals.

Hardness

4-5

Mohs

Luster

Vitreous

Streak

White

Transparency

Translucent

mineralrareArrojadite Group family

Arrojadite-(KNa)

Hardness: 4-5
Luster: Vitreous
Streak: White
Transparency: Translucent

No image

Is this arrojadite-(kna)?

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 arrojadite-(kna) with a known reference. Arrojadite-(KNa) sits at Mohs 4-5 — softer than the next harder reference, harder than the previous one.
2
Check the streak
Drag the specimen across an unglazed porcelain plate. Arrojadite-(KNa) leaves a white streak.
3
Read the luster
Hold the specimen under a strong light. Arrojadite-(KNa) typically shows a vitreous luster.
4
Match the color range
Compare against the expected color range: green, brown, yellowish-green.
5
Look at form & habit
Crystal system: monoclinic. Typical habit: massive, granular, or anhedral grains.

Often confused with

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

Often found alongside arrojadite-(kna)

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

All properties

Chemical formula: KNa₄Ca(Fe²⁺,Mn²⁺)₁₄Al(PO₄)₁₂(OH,F)₂
Mohs hardness: 4-5
Density: 3.5 g/cm³
Colors: Green Brown Yellowish-green
Streak: White
Luster: Vitreous
Transparency: Translucent
Crystal system: Monoclinic
Crystal habit: Massive, Granular, Or Anhedral Grains
Cleavage: Distinct On {010}
Rarity: Rare
Uses: Collector
Host rock: Granite Pegmatites
Typical price: $20-150 thumbnail, $200+ cabinet

Where rockhounds find arrojadite-(kna)

Classic worldwide localities

Palmeira, Brazil
Black Hills, South Dakota, USA
Norrö, Sweden
Hagendorf, Germany

Field-hunting tip

Look in granite pegmatites country — that is the host setting where arrojadite-(kna) typically forms. If you start seeing triphylite, apatite, albite in float, you are in the right ground. Field specimens usually show a massive, granular, or anhedral grains habit, so train your eye for that shape before scanning the outcrop.

Common questions

How do you identify arrojadite-(kna)?+

Mohs hardness is 4-5. It typically shows a vitreous luster. The streak is white. Common colors include green, brown, yellowish-green.

Where is arrojadite-(kna) found?+

Notable localities include Palmeira, Brazil; Black Hills, South Dakota, USA; Norrö, Sweden; Hagendorf, Germany.

How much is arrojadite-(kna) worth?+

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

What rocks look like arrojadite-(kna)?+

Arrojadite-(KNa) is most often confused with Triplite. A quick hardness test and a streak check separate the look-alikes faster than color alone.

What minerals are found with arrojadite-(kna)?+

Arrojadite-(KNa) commonly co-occurs with Triphylite, Apatite, Albite, Quartz, Muscovite. Spotting any of these in float or country rock is a useful trip signal.

What kind of rock does arrojadite-(kna) form in?+

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

What is arrojadite-(kna) used for?+

Arrojadite-(KNa) is used in collector.

Find arrojadite-(kna) on the map

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