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 3.5, softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Streak: white.
- 3Read the lusterHold the specimen under a strong light. Luster: vitreous.
- 4Match the color rangeCompare against the expected color range: white, colorless.
- 5Look at form & habitCrystal system: monoclinic. Typical habit: prismatic, radial, striated.
Often confused with
Brandtite vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Streak differs, so Brandtite leaves white, Roselite leaves light red.
How to tell apart: Gaitite is the harder of the two (Mohs ~5 vs. 3.5).
How to tell apart: Talmessite is the harder of the two (Mohs 5 vs. 3.5).
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
- 3.5
- Density
- 3.61-3.67 g/cm³
- Streak
- White
- Luster
- Vitreous
- Transparency
- Transparent to translucent
- Crystal system
- Monoclinic
- Crystal habit
- Prismatic, radial, striated
- Cleavage
- {010}, perfect; {001}, good
- Rarity
- Rare
- Uses
- Collector
- Host rock
- In metamorphosed Fe–Mn orebody (Harstigen mine and Långban, Sweden); in a metamorphosed stratiform zinc orebody (Sterling Hill, New Jersey, USA)
Where rockhounds find brandtite
Classic worldwide localities
- Sterling Hill, Ogdensburg, Sussex Co., New Jersey, USA
- Found in the Harstigen mine, near Persberg, and at Långban, Värmland, Sweden
- Sailauf, northeast of Aschaffenburg, Bavaria, Germany
- Falotta mine, Oberhalbstein, Graubünden, Switzerland
- Vrančice, near Příbram, Czech Republic
- Ushkatyn-III deposit, Atasu district, Kazakhstan
Field-hunting tip
Where it forms: In metamorphosed Fe–Mn orebody (Harstigen mine and Långban, Sweden); in a metamorphosed stratiform zinc orebody (Sterling Hill, New Jersey, USA). If you start seeing lead, sarkinite, flinkite in float, you are in the right ground. Typical habit: prismatic, radial, striated. Train your eye for that shape before scanning the outcrop.
Common questions
How do you identify brandtite?+
Where is brandtite found?+
Is brandtite safe to handle?+
What rocks look like brandtite?+
What minerals are found with brandtite?+
What kind of rock does brandtite form in?+
What is brandtite used for?+
Find brandtite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
