Melonjosephite is a rare phosphate mineral typically occurring as dark prismatic crystals within granite pegmatites. It is often found associated with other phosphate minerals and quartz, and requires precise chemical analysis for definitive identification due to its similarity to other iron-rich phosphates.

Hardness

Mohs

Luster

Vitreous to resinous

Streak

Greenish

Transparency

Semitransparent

mineralrareDickite Group family

Mélonjosephite

Hardness: <5
Luster: Vitreous to resinous
Streak: Greenish
Transparency: Semitransparent

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Is this mélonjosephite?

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 mélonjosephite with a known reference. Mélonjosephite sits at Mohs <5, softer than the next harder reference, harder than the previous one.
2
Check the streak
Drag the specimen across an unglazed porcelain plate. Streak: greenish.
3
Read the luster
Hold the specimen under a strong light. Luster: vitreous to resinous.
4
Match the color range
Compare against the expected color range: black, dark green.
5
Look at form & habit
Crystal system: orthorhombic. Typical habit: prismatic crystals, aggregates.

Often confused with

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

mineral

Triplite

Mohs 5-5.5

How to tell apart: Streak differs, so Mélonjosephite leaves greenish, Triplite leaves white to brown.

How to tell apart: Streak differs, so Mélonjosephite leaves greenish, Wolfeite leaves white.

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Often found alongside mélonjosephite

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

Triphylite
mineral · Mohs 4-5

All properties

Chemical formula: CaFe²⁺Fe³⁺(PO₄)₂(OH)
Mohs hardness: <5
Density: 3.65 g/cm³
Colors: Black Dark green
Streak: Greenish
Luster: Vitreous to resinous
Transparency: Semitransparent
Crystal system: Orthorhombic
Crystal habit: Prismatic crystals, aggregates
Cleavage: One, longitudinal; another, transverse
Rarity: Rare
Uses: Collector
Host rock: Replacing an alluaudite group mineral in a complex granite pegmatite (Angarf-Sud pegmatite, Morocco)

Where rockhounds find mélonjosephite

Classic worldwide localities

Angarf-Sud pegmatite, Tazenakht Plain, Anti-Atlas Mountains, Morocco
Sandamap pegmatite, west of Usakos, Namibia

Field-hunting tip

Where it forms: Replacing an alluaudite group mineral in a complex granite pegmatite (Angarf-Sud pegmatite, Morocco). If you start seeing triphylite in float, you are in the right ground. Typical habit: prismatic crystals, aggregates. Train your eye for that shape before scanning the outcrop.

Common questions

How do you identify mélonjosephite?+

Mohs hardness is <5. Luster: vitreous to resinous. The streak is greenish. Common colors include black, dark green.

Where is mélonjosephite found?+

Notable localities include Angarf-Sud pegmatite, Tazenakht Plain, Anti-Atlas Mountains, Morocco; Sandamap pegmatite, west of Usakos, Namibia.

What rocks look like mélonjosephite?+

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

What minerals are found with mélonjosephite?+

Mélonjosephite commonly co-occurs with Triphylite. Spotting any of these in float or country rock is a useful trip signal.

What kind of rock does mélonjosephite form in?+

Where it forms: Replacing an alluaudite group mineral in a complex granite pegmatite (Angarf-Sud pegmatite, Morocco). Working float back to the host body is the standard way to chase a fresh occurrence.

What is mélonjosephite used for?+

Mélonjosephite is used in collector.

Find mélonjosephite on the map

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