Stefanweissite is an extremely rare phosphate mineral known primarily from the Gun Claim in the Yukon. It typically forms as small, yellowish-brown platy crystals in association with other rare phosphate species in complex hydrothermal deposits.

Hardness

4.5

Mohs

Luster

Vitreous

Streak

White

Transparency

Translucent

mineralrareGorceixite Group family

Stefanweissite

Hardness: 4.5
Luster: Vitreous
Streak: White
Transparency: Translucent

Is this stefanweissite?

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 stefanweissite with a known reference. Stefanweissite 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. Stefanweissite leaves a white streak.
3
Read the luster
Hold the specimen under a strong light. Stefanweissite typically shows a vitreous luster.
4
Match the color range
Compare against the expected color range: yellow, yellowish-brown.
5
Look at form & habit
Crystal system: monoclinic. Typical habit: platy crystals.

Often confused with

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

How to tell apart: Stefanweissite is noticeably harder (Mohs 4.5 vs. 2); streak differs — Stefanweissite leaves white, Schulenbergite leaves pale green; luster reads vitreous on Stefanweissite and pearly on Schulenbergite.

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Often found alongside stefanweissite

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

All properties

Chemical formula: BaV₂³⁺(PO₄)₂(OH)₂·H₂O
Mohs hardness: 4.5
Density: 3.55 g/cm³
Colors: Yellow Yellowish-brown
Streak: White
Luster: Vitreous
Transparency: Translucent
Crystal system: Monoclinic
Crystal habit: Platy Crystals
Cleavage: None
Rarity: Rare
Uses: Collector
Host rock: Hydrothermal Veins in Shales
Typical price: $100-500+ for micro specimens

Where rockhounds find stefanweissite

Classic worldwide localities

Gun Claim, Yukon, Canada

Field-hunting tip

Look in hydrothermal veins in shales country — that is the host setting where stefanweissite typically forms. If you start seeing vauxite, paravauxite, wardite in float, you are in the right ground. Field specimens usually show a platy crystals habit, so train your eye for that shape before scanning the outcrop.

Common questions

How do you identify stefanweissite?+

Mohs hardness is 4.5. It typically shows a vitreous luster. The streak is white. Common colors include yellow, yellowish-brown.

Where is stefanweissite found?+

Notable localities include Gun Claim, Yukon, Canada.

How much is stefanweissite worth?+

Typical asking prices fall in the range of $100-500+ for micro specimens. Quality, size, and provenance can move individual specimens well outside that range.

What rocks look like stefanweissite?+

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

What minerals are found with stefanweissite?+

Stefanweissite commonly co-occurs with Vauxite, Paravauxite, Wardite. Spotting any of these in float or country rock is a useful trip signal.

What kind of rock does stefanweissite form in?+

Stefanweissite typically forms in hydrothermal veins in shales. Working float back to the host body is the standard way to chase a fresh occurrence.

What is stefanweissite used for?+

Stefanweissite is used in collector.

Find stefanweissite on the map

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