Stumpflite is a rare platinum-antimonide mineral typically found as microscopic grains within massive sulfide deposits in ultramafic rocks. It is usually identified through polished section microscopy in laboratory settings due to its small crystal size and affinity for other platinum-group minerals.

Hardness

Mohs

Luster

Metallic

Streak

Black

Transparency

Opaque

mineralrare

Stumpflite

Hardness: 3
Luster: Metallic
Streak: Black
Transparency: Opaque

Is this stumpflite?

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 stumpflite with a known reference. Stumpflite 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. Stumpflite leaves a black streak.
3
Read the luster
Hold the specimen under a strong light. Stumpflite typically shows a metallic luster.
4
Match the color range
Compare against the expected color range: white, gray.
5
Look at form & habit
Crystal system: hexagonal. Typical habit: grains, inclusions.

Often confused with

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

How to tell apart: Geversite is the harder of the two (Mohs 5.5 vs. 3).

How to tell apart: Genkinite is the harder of the two (Mohs 4 vs. 3).

How to tell apart: Sperrylite is the harder of the two (Mohs 6-7 vs. 3).

Compare →

Often found alongside stumpflite

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

All properties

Chemical formula: Pt(Sb,Bi)
Mohs hardness: 3
Density: 8.55 g/cm³
Colors: White Gray
Streak: Black
Luster: Metallic
Transparency: Opaque
Crystal system: Hexagonal
Crystal habit: Grains, Inclusions
Cleavage: None
Rarity: Rare
Uses: Collector
Host rock: Ultramafic Igneous Complexes
Typical price: $100-500 per specimen

Where rockhounds find stumpflite

Classic worldwide localities

Driekop mine, South Africa
Onverwacht pipe, South Africa
Stillwater complex, USA
Norilsk, Russia

Field-hunting tip

Look in ultramafic igneous complexes country — that is the host setting where stumpflite typically forms. If you start seeing platinum, cooperite, braggite in float, you are in the right ground. Field specimens usually show a grains, inclusions habit, so train your eye for that shape before scanning the outcrop.

Common questions

How do you identify stumpflite?+

Mohs hardness is 3. It typically shows a metallic luster. The streak is black. Common colors include white, gray.

Where is stumpflite found?+

Notable localities include Driekop mine, South Africa; Onverwacht pipe, South Africa; Stillwater complex, USA; Norilsk, Russia.

How much is stumpflite worth?+

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

Is stumpflite safe to handle?+

It contains toxic constituents. Contains antimony and bismuth, which are 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 stumpflite?+

Stumpflite is most often confused with Geversite, Genkinite, Sperrylite. A quick hardness test and a streak check separate the look-alikes faster than color alone.

What minerals are found with stumpflite?+

Stumpflite commonly co-occurs with Platinum, Cooperite, Braggite, Chalcopyrite, Pentlandite. Spotting any of these in float or country rock is a useful trip signal.

What kind of rock does stumpflite form in?+

Stumpflite typically forms in ultramafic igneous complexes. Working float back to the host body is the standard way to chase a fresh occurrence.

What is stumpflite used for?+

Stumpflite is used in collector.

Find stumpflite on the map

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