Keckite is a rare phosphate mineral typically found as brown to yellowish-brown fibrous aggregates or crusts. It primarily occurs as a secondary alteration product of primary phosphate minerals within complex granite pegmatites.

Hardness

3-4

Mohs

Luster

Vitreous

Streak

White

Transparency

Translucent

mineralrareFillowite Group family

Keckite

Hardness: 3-4
Luster: Vitreous
Streak: White
Transparency: Translucent

Is this keckite?

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 keckite with a known reference. Keckite sits at Mohs 3-4 — softer than the next harder reference, harder than the previous one.
2
Check the streak
Drag the specimen across an unglazed porcelain plate. Keckite leaves a white streak.
3
Read the luster
Hold the specimen under a strong light. Keckite typically shows a vitreous luster.
4
Match the color range
Compare against the expected color range: yellowish-brown, brown.
5
Look at form & habit
Crystal system: monoclinic. Typical habit: fibrous, radiating, or crusts.

Often confused with

Keckite vs. its common look-alikes — and how to tell them apart in the field.

mineral

Rockbridgeite

Mohs 4.5

How to tell apart: Streak differs — Keckite leaves white, Rockbridgeite leaves greenish-brown.

Often found alongside keckite

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

All properties

Chemical formula: CaMn²⁺₄Fe³⁺₂(PO₄)₄(OH)₄·2H₂O
Mohs hardness: 3-4
Density: 3.37 g/cm³
Colors: Yellowish-brown Brown
Streak: White
Luster: Vitreous
Transparency: Translucent
Crystal system: Monoclinic
Crystal habit: Fibrous, Radiating, Or Crusts
Cleavage: None
Rarity: Rare
Uses: Collector
Host rock: Granite Pegmatites
Typical price: $50-300 per specimen

Where rockhounds find keckite

Classic worldwide localities

Hagendorf-Pleystein pegmatite, Bavaria, Germany
Mangualde pegmatite, Portugal

Field-hunting tip

Look in granite pegmatites country — that is the host setting where keckite typically forms. If you start seeing triphylite, hureaulite, leucophosphite in float, you are in the right ground. Field specimens usually show a fibrous, radiating, or crusts habit, so train your eye for that shape before scanning the outcrop.

Common questions

How do you identify keckite?+

Mohs hardness is 3-4. It typically shows a vitreous luster. The streak is white. Common colors include yellowish-brown, brown.

Where is keckite found?+

Notable localities include Hagendorf-Pleystein pegmatite, Bavaria, Germany; Mangualde pegmatite, Portugal.

How much is keckite worth?+

Typical asking prices fall in the range of $50-300 per specimen. Quality, size, and provenance can move individual specimens well outside that range.

What rocks look like keckite?+

Keckite is most often confused with Rockbridgeite, Strengite. A quick hardness test and a streak check separate the look-alikes faster than color alone.

What minerals are found with keckite?+

Keckite commonly co-occurs with Triphylite, Hureaulite, Leucophosphite, Mitridatite. Spotting any of these in float or country rock is a useful trip signal.

What kind of rock does keckite form in?+

Keckite typically forms in granite pegmatites. Working float back to the host body is the standard way to chase a fresh occurrence.

What is keckite used for?+

Keckite is used in collector.

Find keckite on the map

RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.