Wallkilldellite-(Fe) is a rare arsenate mineral characterized by its reddish-brown platy crystals and radial habits. It is primarily found in the metamorphosed zinc ore deposits of the Sterling Hill Mine, where it occurs as a late-stage secondary mineral. Collectors value it for its limited occurrence and relationship to other rare Franklin-area arsenates.

Hardness

Mohs

Luster

Vitreous

Streak

Light Brown

Transparency

Translucent

mineralrareWallkilldellite Group family

Wallkilldellite-(Fe)

Hardness: 3
Luster: Vitreous
Streak: Light Brown
Transparency: Translucent

Is this wallkilldellite-(fe)?

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 wallkilldellite-(fe) with a known reference. Wallkilldellite-(Fe) sits at Mohs 3 — softer than the next harder reference, harder than the previous one.
2
Check the streak
Drag the specimen across an unglazed porcelain plate. Wallkilldellite-(Fe) leaves a light brown streak.
3
Read the luster
Hold the specimen under a strong light. Wallkilldellite-(Fe) typically shows a vitreous luster.
4
Match the color range
Compare against the expected color range: red, brown, reddish-brown.
5
Look at form & habit
Crystal system: trigonal. Typical habit: platy crystals, radial aggregates.

Often confused with

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

How to tell apart: Streak differs — Wallkilldellite-(Fe) leaves light brown, Wallkilldellite leaves yellowish-orange.

How to tell apart: Streak differs — Wallkilldellite-(Fe) leaves light brown, Chlorophoenicite leaves white.

Compare →

Often found alongside wallkilldellite-(fe)

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

All properties

Chemical formula: (Ca,Mn)₄Fe³⁺₂(AsO₄)₂(OH)₈·5H₂O
Mohs hardness: 3
Density: 3.37 g/cm³
Colors: Red Brown Reddish-brown
Streak: Light Brown
Luster: Vitreous
Transparency: Translucent
Crystal system: Trigonal
Crystal habit: Platy Crystals, Radial Aggregates
Cleavage: Perfect On {0001}
Rarity: Rare
Uses: Collector
Host rock: Metamorphosed Zinc Ore Deposits
Typical price: $50-300 per specimen

Where rockhounds find wallkilldellite-(fe)

Classic worldwide localities

Sterling Hill Mine, New Jersey, USA

Field-hunting tip

Look in metamorphosed zinc ore deposits country — that is the host setting where wallkilldellite-(fe) typically forms. If you start seeing arsenates, calcite, franklinite in float, you are in the right ground. Field specimens usually show a platy crystals, radial aggregates habit, so train your eye for that shape before scanning the outcrop.

Common questions

How do you identify wallkilldellite-(fe)?+

Mohs hardness is 3. It typically shows a vitreous luster. The streak is light brown. Common colors include red, brown, reddish-brown.

Where is wallkilldellite-(fe) found?+

Notable localities include Sterling Hill Mine, New Jersey, USA.

How much is wallkilldellite-(fe) 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.

Is wallkilldellite-(fe) safe to handle?+

It contains toxic constituents. Contains arsenic, which is toxic. Handle with care, avoid creating dust, and wash hands thoroughly after handling. Handle with care, avoid grinding or breathing dust, and store separately.

What rocks look like wallkilldellite-(fe)?+

Wallkilldellite-(Fe) is most often confused with Wallkilldellite, Chlorophoenicite. A quick hardness test and a streak check separate the look-alikes faster than color alone.

What minerals are found with wallkilldellite-(fe)?+

Wallkilldellite-(Fe) commonly co-occurs with Arsenates, Calcite, Franklinite, Willemite. Spotting any of these in float or country rock is a useful trip signal.

What kind of rock does wallkilldellite-(fe) form in?+

Wallkilldellite-(Fe) typically forms in metamorphosed zinc ore deposits. Working float back to the host body is the standard way to chase a fresh occurrence.

What is wallkilldellite-(fe) used for?+

Wallkilldellite-(Fe) is used in collector.

Find wallkilldellite-(fe) on the map

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