Bismutoferrite is an uncommon bismuth-iron silicate that typically forms as a fine-grained, earthy or massive material in hydrothermal deposits. It is best identified by its distinct yellowish-green to olive-green color and its association with other bismuth secondary minerals. It is primarily sought by advanced collectors of bismuth-bearing species.
Is this bismutoferrite?
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 bismutoferrite with a known reference. Bismutoferrite sits at Mohs 3.5-4, softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Bismutoferrite leaves a yellowish-green streak.
- 3Read the lusterHold the specimen under a strong light. Bismutoferrite typically shows a dull luster.
- 4Match the color rangeCompare against the expected color range: yellow, greenish-yellow, olive-green, brown.
- 5Look at form & habitCrystal system: monoclinic. Typical habit: massive, earthy, or granular aggregates.
Often confused with
Bismutoferrite vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Streak differs, so Bismutoferrite leaves yellowish-green, Mixite leaves white; luster reads dull on Bismutoferrite and vitreous on Mixite.
How to tell apart: Streak differs, so Bismutoferrite leaves yellowish-green, Chrysocolla leaves white; luster reads dull on Bismutoferrite and vitreous on Chrysocolla.
How to tell apart: Streak differs, so Bismutoferrite leaves yellowish-green, Bismutite leaves white; luster reads dull on Bismutoferrite and pearly on Bismutite.
Often found alongside bismutoferrite
Minerals reported to co-occur with bismutoferrite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- BiFe³⁺₂(SiO₄)(OH)₃
- Mohs hardness
- 3.5-4
- Density
- 4.5-4.8 g/cm³
- Streak
- Yellowish-green
- Luster
- Dull
- Transparency
- Opaque
- Crystal system
- Monoclinic
- Crystal habit
- Massive, Earthy, Or Granular Aggregates
- Cleavage
- None
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Hydrothermal Veins Containing Bismuth and Iron Minerals
- Typical price
- $20-150 thumbnail, $200+ cabinet specimen
Where rockhounds find bismutoferrite
Classic worldwide localities
- Schneeberg, Saxony, Germany
- Joachimsthal, Czech Republic
- Tinkers Knob, New South Wales, Australia
- Gunnison County, Colorado, USA
Field-hunting tip
Look in hydrothermal veins containing bismuth and iron minerals country, the host setting where bismutoferrite typically forms. If you start seeing bismutite, quartz, pyrite in float, you are in the right ground. Field specimens usually show a massive, earthy, or granular aggregates habit, so train your eye for that shape before scanning the outcrop.
Common questions
How do you identify bismutoferrite?+
Where is bismutoferrite found?+
How much is bismutoferrite worth?+
Is bismutoferrite safe to handle?+
What rocks look like bismutoferrite?+
What minerals are found with bismutoferrite?+
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Find bismutoferrite on the map
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