Synadelphite is a rare manganese arsenate mineral typically found as reddish-brown prismatic crystals or radial clusters. It is highly valued by mineral collectors for its complexity and association with the unique manganese deposits of Långban, Sweden.
Is this synadelphite?
5-step field checkRun through these checks against the specimen in your hand. The more boxes tick, the more confident the ID.
- 1Test the hardnessTry to scratch synadelphite with a known reference. Synadelphite sits at Mohs 4.5, softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Synadelphite leaves a yellowish-brown streak.
- 3Read the lusterHold the specimen under a strong light. Synadelphite typically shows a vitreous to greasy luster.
- 4Match the color rangeCompare against the expected color range: brown, reddish-brown, yellowish-brown.
- 5Look at form & habitCrystal system: orthorhombic. Typical habit: prismatic crystals, radial aggregates, crusts.
Often confused with
Synadelphite vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Streak differs, so Synadelphite leaves yellowish-brown, Allactite leaves light brown; luster reads vitreous to greasy on Synadelphite and vitreous on Allactite.
How to tell apart: Streak differs, so Synadelphite leaves yellowish-brown, Brandtite leaves white; luster reads vitreous to greasy on Synadelphite and vitreous on Brandtite.
How to tell apart: Streak differs, so Synadelphite leaves yellowish-brown, Adelite leaves white; luster reads vitreous to greasy on Synadelphite and vitreous on Adelite.
Often found alongside synadelphite
Minerals reported to co-occur with synadelphite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Mn²⁺₉(As³⁺O₃)(As⁵⁺O₄)₂(OH)₉
- Mohs hardness
- 4.5
- Density
- 3.5 g/cm³
- Streak
- Yellowish-brown
- Luster
- Vitreous to Greasy
- Transparency
- Translucent
- Crystal system
- Orthorhombic
- Crystal habit
- Prismatic Crystals, Radial Aggregates, Crusts
- Cleavage
- Perfect On {001}
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Metamorphosed Manganese Ore Deposits
- Typical price
- $50-300 for small thumbnail specimens
Where rockhounds find synadelphite
Classic worldwide localities
- Nordmark, Värmland, Sweden
- Långban, Värmland, Sweden
Field-hunting tip
Look in metamorphosed manganese ore deposits country, the host setting where synadelphite typically forms. If you start seeing hausmannite, barite, svabite in float, you are in the right ground. Field specimens usually show a prismatic crystals, radial aggregates, crusts habit, so train your eye for that shape before scanning the outcrop.
Common questions
How do you identify synadelphite?+
Where is synadelphite found?+
How much is synadelphite worth?+
Is synadelphite safe to handle?+
What rocks look like synadelphite?+
What minerals are found with synadelphite?+
What kind of rock does synadelphite form in?+
What is synadelphite used for?+
Find synadelphite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
