Sursassite is a rare manganese aluminum silicate typically found as reddish-brown fibrous or radiating needle-like crystals. It is most commonly identified in manganese-rich metamorphic deposits, often associated with braunite and quartz. Collectors usually seek it out as micro-specimens from its type locality in the Swiss Alps.

Hardness

6.5-7

Mohs

Luster

Vitreous

Streak

White

Transparency

Translucent

mineralrarePumpellyite Group family

Sursassite

Hardness: 6.5-7
Luster: Vitreous
Streak: White
Transparency: Translucent

Is this sursassite?

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 sursassite with a known reference. Sursassite sits at Mohs 6.5-7, softer than the next harder reference, harder than the previous one.
2
Check the streak
Drag the specimen across an unglazed porcelain plate. Sursassite leaves a white streak.
3
Read the luster
Hold the specimen under a strong light. Sursassite typically shows a vitreous luster.
4
Match the color range
Compare against the expected color range: reddish-brown, brown.
5
Look at form & habit
Crystal system: monoclinic. Typical habit: fibrous, radiating aggregates, massive.

Often confused with

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

Often found alongside sursassite

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

All properties

Chemical formula: Mn²⁺₂Al₃(Si₂O₇)(SiO₄)O(OH)₃
Mohs hardness: 6.5-7
Density: 3.37 g/cm³
Colors: Reddish-brown Brown
Streak: White
Luster: Vitreous
Transparency: Translucent
Crystal system: Monoclinic
Crystal habit: Fibrous, Radiating Aggregates, Massive
Cleavage: None
Rarity: Rare
Uses: Collector
Host rock: Manganiferous Metamorphic Rocks
Typical price: $20-150 for thumbnail specimens

Where rockhounds find sursassite

Classic worldwide localities

Graubünden, Switzerland
Val d'Err, Switzerland
Ogliastra, Italy

Field-hunting tip

Look in manganiferous metamorphic rocks country, the host setting where sursassite typically forms. If you start seeing quartz, braunite, tansanite in float, you are in the right ground. Field specimens usually show a fibrous, radiating aggregates, massive habit, so train your eye for that shape before scanning the outcrop.

Common questions

How do you identify sursassite?+

Mohs hardness is 6.5-7. It typically shows a vitreous luster. The streak is white. Common colors include reddish-brown, brown.

Where is sursassite found?+

Notable localities include Graubünden, Switzerland; Val d'Err, Switzerland; Ogliastra, Italy.

How much is sursassite worth?+

Typical asking prices fall in the range of $20-150 for thumbnail specimens. Quality, size, and provenance can move individual specimens well outside that range.

What rocks look like sursassite?+

Sursassite is most often confused with Epidote. A quick hardness test and a streak check separate the look-alikes faster than color alone.

What minerals are found with sursassite?+

Sursassite commonly co-occurs with Quartz, Braunite, Tansanite, Hollandite. Spotting any of these in float or country rock is a useful trip signal.

What kind of rock does sursassite form in?+

Sursassite typically forms in manganiferous metamorphic rocks. Working float back to the host body is the standard way to chase a fresh occurrence.

What is sursassite used for?+

Sursassite is used in collector.

Find sursassite on the map

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