Sursassite is a rare manganese aluminum silicate typically found as reddish-copper-red 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

Mohs

Luster

Vitreous

Streak

Yellowish brown

Transparency

Semitransparent

mineralrarePumpellyite Group family

Sursassite

Hardness: 3
Luster: Vitreous
Streak: Yellowish brown
Transparency: Semitransparent

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 3, softer than the next harder reference, harder than the previous one.
2
Check the streak
Drag the specimen across an unglazed porcelain plate. Streak: yellowish brown.
3
Read the luster
Hold the specimen under a strong light. Luster: vitreous.
4
Match the color range
Compare against the expected color range: copper red, deep reddish brown.
5
Look at form & habit
Crystal system: monoclinic. Typical habit: botryoidal, radial.

Often confused with

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

mineral

Epidote

Mohs 6-7

How to tell apart: Epidote is the harder of the two (Mohs 6-7 vs. 3); streak differs, so Sursassite leaves yellowish brown, Epidote leaves grayish white.

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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: Mn₂Al₃(SiO₄)(Si₂O₇)(OH)₃
Mohs hardness: 3
Density: 3.256 g/cm³
Colors: Copper redDeep reddish brown
Streak: Yellowish brown
Luster: Vitreous
Transparency: Semitransparent
Crystal system: Monoclinic
Crystal habit: Botryoidal, radial
Cleavage: On {001} and {101}
Rarity: Rare
Uses: Collector
Host rock: As vein fillings in manganese deposits in low-grade metasediments

Where rockhounds find sursassite

Classic worldwide localities

Palos Verdes Hills, Los Angeles Co., California, USA
Val d'Err, Oberhalbstein, Graubünden, Switzerland
Plymouth deposit, near Woodstock, New Brunswick, Canada
Molinello manganese mine, near Chiavari, Val Graveglia, Liguria, Italy
Andros Island, Cyclades Islands, Greece

Field-hunting tip

Where it forms: As vein fillings in manganese deposits in low-grade metasediments. If you start seeing braunite, barite, calcite in float, you are in the right ground. Typical habit: botryoidal, radial. Train your eye for that shape before scanning the outcrop.

Common questions

How do you identify sursassite?+

Mohs hardness is 3. Luster: vitreous. The streak is yellowish brown. Common colors include copper red, deep reddish brown.

Where is sursassite found?+

Notable localities include Palos Verdes Hills, Los Angeles Co., California, USA; Val d'Err, Oberhalbstein, Graubünden, Switzerland; Plymouth deposit, near Woodstock, New Brunswick, Canada; Molinello manganese mine, near Chiavari, Val Graveglia, Liguria, Italy; Andros Island, Cyclades Islands, Greece.

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 Braunite, Barite, Calcite, Quartz. Spotting any of these in float or country rock is a useful trip signal.

What kind of rock does sursassite form in?+

Where it forms: As vein fillings in manganese deposits in low-grade metasediments. 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.