Sundiusite is an extremely rare lead sulfate-chloride mineral first discovered in the famous Långban mines of Sweden. It typically occurs as small, clear, tabular crystals embedded in manganese-rich metamorphic rocks. Due to its extreme rarity, it is highly sought after by advanced mineral collectors specializing in lead species.

Hardness

Mohs

Luster

Vitreous

Streak

White

Transparency

Transparent

mineralrare

Sundiusite

Hardness: 3
Luster: Vitreous
Streak: White
Transparency: Transparent

Is this sundiusite?

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 sundiusite with a known reference. Sundiusite 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. Sundiusite leaves a white streak.
3
Read the luster
Hold the specimen under a strong light. Sundiusite typically shows a vitreous luster.
4
Match the color range
Compare against the expected color range: white, colorless.
5
Look at form & habit
Crystal system: monoclinic. Typical habit: tabular crystals.

Often confused with

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

mineral

Penfieldite

Mohs 2.5

How to tell apart: Luster reads vitreous on Sundiusite and adamantine on Penfieldite.

How to tell apart: Luster reads vitreous on Sundiusite and adamantine on Laurionite.

Compare →

Often found alongside sundiusite

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

All properties

Chemical formula: Pb₁₀(SO₄)Cl₂(OH)₁₂O
Mohs hardness: 3
Density: 3.55 g/cm³
Colors: White Colorless
Streak: White
Luster: Vitreous
Transparency: Transparent
Crystal system: Monoclinic
Crystal habit: Tabular Crystals
Cleavage: Perfect
Rarity: Rare
Uses: Collector
Host rock: Metamorphosed Iron-manganese Ore Deposits
Typical price: $100-500 per specimen

Where rockhounds find sundiusite

Classic worldwide localities

Långban, Sweden

Field-hunting tip

Look in metamorphosed iron-manganese ore deposits country — that is the host setting where sundiusite typically forms. If you start seeing långbanite, hematite, hausmannite in float, you are in the right ground. Field specimens usually show a tabular crystals habit, so train your eye for that shape before scanning the outcrop.

Common questions

How do you identify sundiusite?+

Mohs hardness is 3. It typically shows a vitreous luster. The streak is white. Common colors include white, colorless.

Where is sundiusite found?+

Notable localities include Långban, Sweden.

How much is sundiusite 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 sundiusite safe to handle?+

It contains toxic constituents. Contains lead, which is toxic if ingested or inhaled as dust. Wash hands thoroughly after handling and keep away from food. Handle with care, avoid grinding or breathing dust, and store separately.

What rocks look like sundiusite?+

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

What minerals are found with sundiusite?+

Sundiusite commonly co-occurs with Långbanite, Hematite, Hausmannite. Spotting any of these in float or country rock is a useful trip signal.

What kind of rock does sundiusite form in?+

Sundiusite typically forms in metamorphosed iron-manganese ore deposits. Working float back to the host body is the standard way to chase a fresh occurrence.

What is sundiusite used for?+

Sundiusite is used in collector.

Find sundiusite on the map

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