Brandtite is a rare hydrated calcium manganese arsenate mineral that typically forms as small, clear to white crystals in manganese-rich metamorphic environments. It is most frequently collected from the famous Langban mines in Sweden or the Franklin/Sterling Hill districts in New Jersey, where it is often associated with other rare arsenate species. Due to its arsenic content, it should be stored in a sealed container and handled with caution.
Is this brandtite?
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 brandtite with a known reference. Brandtite sits at Mohs 3-4 — softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Brandtite leaves a white streak.
- 3Read the lusterHold the specimen under a strong light. Brandtite typically shows a vitreous luster.
- 4Match the color rangeCompare against the expected color range: white, colorless, pale yellow, pale pink.
- 5Look at form & habitCrystal system: monoclinic. Typical habit: prismatic to tabular crystals, sometimes crusts or radial aggregates.
Often confused with
Brandtite vs. its common look-alikes — and how to tell them apart in the field.
Often found alongside brandtite
Minerals reported to co-occur with brandtite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Ca₂Mn(AsO₄)₂·2H₂O
- Mohs hardness
- 3-4
- Density
- 3.37 g/cm³
- Streak
- White
- Luster
- Vitreous
- Transparency
- Transparent
- Crystal system
- Monoclinic
- Crystal habit
- Prismatic to Tabular Crystals, Sometimes Crusts or Radial Aggregates
- Cleavage
- Distinct On {010}
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Metamorphosed Manganese Ore Deposits
- Typical price
- $20-150 for thumbnail to small cabinet specimens
Where rockhounds find brandtite
Classic worldwide localities
- Langban, Sweden
- Franklin, New Jersey, USA
- Sterling Hill, New Jersey, USA
- Jakobsberg, Sweden
Field-hunting tip
Look in metamorphosed manganese ore deposits country — that is the host setting where brandtite typically forms. If you start seeing hausmannite, barite, calcite in float, you are in the right ground. Field specimens usually show a prismatic to tabular crystals, sometimes crusts or radial aggregates habit, so train your eye for that shape before scanning the outcrop.
Common questions
How do you identify brandtite?+
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How much is brandtite worth?+
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Find brandtite on the map
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