Erlianite is a rare phyllosilicate mineral typically found as fibrous or platy brownish aggregates within iron-rich chert formations. It was first identified in China and is highly sought after by systematic mineral collectors due to its restricted locality and complex chemical structure.
Is this erlianite?
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 erlianite with a known reference. Erlianite sits at Mohs 3-4, softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Erlianite leaves a yellowish-brown streak.
- 3Read the lusterHold the specimen under a strong light. Erlianite typically shows a vitreous luster.
- 4Match the color rangeCompare against the expected color range: brown, yellowish-brown, dark brown.
- 5Look at form & habitCrystal system: trigonal. Typical habit: fibrous, radiated aggregates, platy crystals.
Often confused with
Erlianite vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Streak differs, so Erlianite leaves yellowish-brown, Stilpnomelane leaves yellowish-brown to greenish-black; luster reads vitreous on Erlianite and pearly on Stilpnomelane.
How to tell apart: Erlianite is noticeably harder (Mohs 3-4 vs. 1-2); streak differs, so Erlianite leaves yellowish-brown, Minnesotaite leaves white; luster reads vitreous on Erlianite and pearly on Minnesotaite.
How to tell apart: Streak differs, so Erlianite leaves yellowish-brown, Greenalite leaves pale yellow; luster reads vitreous on Erlianite and resinous on Greenalite.
Often found alongside erlianite
Minerals reported to co-occur with erlianite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- (Fe,Mg,Fe)₄Si₆O₁₅(OH)₂·4H₂O
- Mohs hardness
- 3-4
- Density
- 2.88 g/cm³
- Streak
- Yellowish-brown
- Luster
- Vitreous
- Transparency
- Translucent
- Crystal system
- Trigonal
- Crystal habit
- Fibrous, Radiated Aggregates, Platy Crystals
- Cleavage
- Perfect
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Iron-rich Sedimentary Chert Formations
- Typical price
- $20-150 thumbnail specimens
Where rockhounds find erlianite
Classic worldwide localities
- Erlianshan, Gansu Province, China
Field-hunting tip
Look in iron-rich sedimentary chert formations country, the host setting where erlianite typically forms. If you start seeing quartz, magnetite, hematite in float, you are in the right ground. Field specimens usually show a fibrous, radiated aggregates, platy crystals habit, so train your eye for that shape before scanning the outcrop.
Common questions
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Find erlianite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
