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 — Bismutoferrite leaves yellowish-green, Mixite leaves white; luster reads dull on Bismutoferrite and vitreous on Mixite.
How to tell apart: Streak differs — Bismutoferrite leaves yellowish-green, Chrysocolla leaves white; luster reads dull on Bismutoferrite and vitreous on Chrysocolla.
How to tell apart: Streak differs — 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 — that is 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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