Suanite is a rare magnesium borate mineral typically found in high-temperature contact metamorphic skarns. It usually occurs as white to colorless prismatic crystals or fibrous masses closely associated with ludwigite and carbonate minerals.
Is this suanite?
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 suanite with a known reference. Suanite sits at Mohs 5.5, softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Streak: white.
- 3Read the lusterHold the specimen under a strong light. Luster: silky to pearly.
- 4Match the color rangeCompare against the expected color range: white, gray white.
- 5Look at form & habitCrystal system: monoclinic. Typical habit: prismatic crystals, radial aggregates, fibrous masses.
Often confused with
Suanite vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Luster reads silky to pearly on Suanite and vitreous on Tremolite.
How to tell apart: Suanite is noticeably harder (Mohs 5.5 vs. 3.5-4); streak differs, so Suanite leaves white, Warwickite leaves bluish black; luster reads silky to pearly on Suanite and subvitreous to pearly, submetallic on cleavages, commonly dull if altered on Warwickite.
How to tell apart: Sinhalite is the harder of the two (Mohs 6.5-7 vs. 5.5); luster reads silky to pearly on Suanite and vitreous on Sinhalite.
Often found alongside suanite
Minerals reported to co-occur with suanite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Mg₂B₂O₅
- Mohs hardness
- 5.5
- Density
- 2.91 g/cm³
- Colors
- Streak
- White
- Luster
- Silky to pearly
- Transparency
- Translucent
- Crystal system
- Monoclinic
- Crystal habit
- Prismatic crystals, radial aggregates, fibrous masses
- Cleavage
- Perfect
- Rarity
- Rare
- Uses
- Collector
- Host rock
- In a contact metasomatic hydrothermal boron deposit in diopside–clinohumite– dolomite–calcite skarn (Hol Kol mine, North Korea)
Where rockhounds find suanite
Classic worldwide localities
- Hol Kol Au–Cu mine, about 75 km southeast of Pyongyang, Suan Co., North Korea
- Zhuanmiao and Houxianyu boron deposits, Liaoning Province, China
- Sakha, from the Titovskoye boron–iron deposit, Tas-Khayakhtakh Mountains, in the Taiga boron–iron deposit, and from the Tayozhnoye iron deposit, 550 km south of Yakutsk, Russia
- Băiţa (Rézbánya), Băişoara, Cacova Ierii, Gilǎu Mountains, Romania
- Kami-neichi, Miyako, Iwate Prefecture, Japan
Field-hunting tip
Where it forms: In a contact metasomatic hydrothermal boron deposit in diopside–clinohumite– dolomite–calcite skarn (Hol Kol mine, North Korea). If you start seeing kotoite, sakhaite, ludwigite in float, you are in the right ground. Typical habit: prismatic crystals, radial aggregates, fibrous masses. Train your eye for that shape before scanning the outcrop.
Common questions
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Find suanite on the map
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