Krettnichite is a very rare secondary mineral member of the Tsumcorite group, typically found as small tabular crystals or thin crusts in oxidized mineral deposits. It is chemically notable for its manganese content and is highly sought after by advanced mineral collectors for its limited type locality occurrences.
Is this krettnichite?
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 krettnichite with a known reference. Krettnichite 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. Streak: brown.
- 3Read the lusterHold the specimen under a strong light. Luster: adamantine.
- 4Match the color rangeCompare against the expected color range: dark brown, black.
- 5Look at form & habitCrystal system: monoclinic. Typical habit: aggregates, platy, radial.
Often confused with
Krettnichite vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Streak differs, so Krettnichite leaves brown, Tsumcorite leaves yellow; luster reads adamantine on Krettnichite and vitreous on Tsumcorite.
How to tell apart: Streak differs, so Krettnichite leaves brown, Helmutwinklerite leaves white; luster reads adamantine on Krettnichite and vitreous, resinous on fracture surfaces on Helmutwinklerite.
Often found alongside krettnichite
Minerals reported to co-occur with krettnichite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- PbMn₂(VO₄)₂(OH)₂
- Mohs hardness
- 4.5
- Density
- 4.51-4.81 g/cm³
- Colors
- Streak
- Brown
- Luster
- Adamantine
- Transparency
- Opaque, transparent as thin plates
- Crystal system
- Monoclinic
- Crystal habit
- Aggregates, platy, radial
- Cleavage
- Perfect ∥ (001), another distinct set intersecting (001) at a high angle visible in polished section
- Rarity
- Rare
- Uses
- Collector
- Host rock
- As a primary accessory ore mineral and as free crystals in vugs within a non-metamorphosed, hydrothermal manganite-quartz vein
Where rockhounds find krettnichite
Classic worldwide localities
- Krettnich, Saarland, Germany (type locality)
Field-hunting tip
Where it forms: As a primary accessory ore mineral and as free crystals in vugs within a non-metamorphosed, hydrothermal manganite-quartz vein. If you start seeing barite, ankerite, manganite in float, you are in the right ground. Typical habit: aggregates, platy, radial. Train your eye for that shape before scanning the outcrop.
Common questions
How do you identify krettnichite?+
Where is krettnichite found?+
Is krettnichite safe to handle?+
What rocks look like krettnichite?+
What minerals are found with krettnichite?+
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Find krettnichite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
