Fredrikssonite is a rare manganese-magnesium borate mineral that typically forms as small, prismatic crystals within metamorphosed ore bodies. It is famously associated with the Långban deposit in Sweden, often appearing as distinct, colored crystals embedded in a matrix of other manganese minerals. Collectors prize it for its unique chemistry and extreme rarity in fine crystal form.
Is this fredrikssonite?
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 fredrikssonite with a known reference. Fredrikssonite sits at Mohs 6 — softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Fredrikssonite leaves a white streak.
- 3Read the lusterHold the specimen under a strong light. Fredrikssonite typically shows a vitreous luster.
- 4Match the color rangeCompare against the expected color range: yellow, brown, orange-brown.
- 5Look at form & habitCrystal system: orthorhombic. Typical habit: prismatic crystals.
Often confused with
Fredrikssonite vs. its common look-alikes — and how to tell them apart in the field.
How to tell apart: Fredrikssonite is noticeably harder (Mohs 6 vs. 5); streak differs — Fredrikssonite leaves white, Ludwigite leaves black; luster reads vitreous on Fredrikssonite and submetallic on Ludwigite.
How to tell apart: Fredrikssonite is noticeably harder (Mohs 6 vs. 5); streak differs — Fredrikssonite leaves white, Vonsenite leaves black; luster reads vitreous on Fredrikssonite and submetallic on Vonsenite.
Often found alongside fredrikssonite
Minerals reported to co-occur with fredrikssonite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Mg₂(Mn³⁺,Fe³⁺)(BO₃)O₂
- Mohs hardness
- 6
- Density
- 4.15 g/cm³
- Colors
- Streak
- White
- Luster
- Vitreous
- Transparency
- Translucent
- Crystal system
- Orthorhombic
- Crystal habit
- Prismatic Crystals
- Cleavage
- None
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Metamorphosed Manganese Ore Deposits
- Typical price
- $100-500 per specimen
Where rockhounds find fredrikssonite
Classic worldwide localities
- Långban, Sweden
Field-hunting tip
Look in metamorphosed manganese ore deposits country — that is the host setting where fredrikssonite typically forms. If you start seeing hausmannite, jacobsite, dolomite in float, you are in the right ground. Field specimens usually show a prismatic crystals habit, so train your eye for that shape before scanning the outcrop.
Common questions
How do you identify fredrikssonite?+
Where is fredrikssonite found?+
How much is fredrikssonite worth?+
What rocks look like fredrikssonite?+
What minerals are found with fredrikssonite?+
What kind of rock does fredrikssonite form in?+
What is fredrikssonite used for?+
Find fredrikssonite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
