Yuanfuliite is an uncommon borate mineral typically found as elongated prisms or needle-like crystals in magnesite skarns. It was first identified in China and is highly prized by collectors for its distinct orthorhombic form and association with other rare borate species.
Is this yuanfuliite?
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 yuanfuliite with a known reference. Yuanfuliite sits at Mohs 5-6, softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Streak: black.
- 3Read the lusterHold the specimen under a strong light. Luster: submetallic to adamantine.
- 4Match the color rangeCompare against the expected color range: black.
- 5Look at form & habitCrystal system: orthorhombic. Typical habit: disseminated.
Often confused with
Yuanfuliite vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Yuanfuliite is noticeably harder (Mohs 5-6 vs. 3.5-4); streak differs, so Yuanfuliite leaves black, Warwickite leaves bluish black; luster reads submetallic to adamantine on Yuanfuliite and subvitreous to pearly, submetallic on cleavages, commonly dull if altered on Warwickite.
Often found alongside yuanfuliite
Minerals reported to co-occur with yuanfuliite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Mg(Fe³⁺,Al)O(BO₃)
- Mohs hardness
- 5-6
- Density
- 4.02 g/cm³
- Colors
- Streak
- Black
- Luster
- Submetallic to adamantine
- Transparency
- Opaque
- Crystal system
- Orthorhombic
- Crystal habit
- Disseminated
- Cleavage
- Perfect on {100}
- Rarity
- Rare
- Uses
- Collector
- Host rock
- In metamorphosed magnesian marble in a boron deposit (Zhuanmiao deposit, China); in ultramafic rocks (Inglefield Land, Greenland)
Where rockhounds find yuanfuliite
Classic worldwide localities
- Zhuanmiao boron deposit, Kuandian Co., and the Huayuangou boron deposit, both in Liaoning Province, China
- Found in central Inglefield Land, northwest Greenland
Field-hunting tip
Where it forms: In metamorphosed magnesian marble in a boron deposit (Zhuanmiao deposit, China); in ultramafic rocks (Inglefield Land, Greenland). If you start seeing suanite, anhydrite, apatite in float, you are in the right ground. Typical habit: disseminated. Train your eye for that shape before scanning the outcrop.
Common questions
How do you identify yuanfuliite?+
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What rocks look like yuanfuliite?+
What minerals are found with yuanfuliite?+
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Find yuanfuliite on the map
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