Yimengite is a rare potassium-rich oxide mineral typically found as small, black, hexagonal tabular crystals within diamond-bearing kimberlite pipes. It is primarily recognized by collectors of rare earth and oxide minerals, as it is only known from specific kimberlite occurrences in China.
Is this yimengite?
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 yimengite with a known reference. Yimengite sits at Mohs 4.1, softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Streak: brown.
- 3Read the lusterHold the specimen under a strong light. Luster: metallic.
- 4Match the color rangeCompare against the expected color range: black.
- 5Look at form & habitCrystal system: hexagonal. Typical habit: platy, selvage, tabular.
Often confused with
Yimengite vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Magnetoplumbite is the harder of the two (Mohs 6 vs. 4.1); streak differs, so Yimengite leaves brown, Magnetoplumbite leaves dark brown.
How to tell apart: Hawthorneite is the harder of the two (Mohs ~5.8 vs. 4.1); streak differs, so Yimengite leaves brown, Hawthorneite leaves black.
How to tell apart: Ilmenite is the harder of the two (Mohs 5-6 vs. 4.1); streak differs, so Yimengite leaves brown, Ilmenite leaves black to reddish brown.
Often found alongside yimengite
Minerals reported to co-occur with yimengite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- K[Ti₃Cr₅Fe₂Mg₂]O₁₉
- Mohs hardness
- 4.1
- Density
- 4.34 g/cm³
- Colors
- Streak
- Brown
- Luster
- Metallic
- Transparency
- Opaque
- Crystal system
- Hexagonal
- Crystal habit
- Platy, selvage, tabular
- Cleavage
- {0001}, perfect; {1121}, good; {1011}, poor
- Rarity
- Rare
- Uses
- Collector
- Host rock
- A metasomatic alteration product of chromian spinel in kimberlites
Where rockhounds find yimengite
Classic worldwide localities
- Yimeng Mountain area, Shandong Province, China
- Guaniamo district, Bolivar Province, Venezuela
Field-hunting tip
Where it forms: A metasomatic alteration product of chromian spinel in kimberlites. If you start seeing chromian spinel, mathiasite, olivine in float, you are in the right ground. Typical habit: platy, selvage, tabular. Train your eye for that shape before scanning the outcrop.
Common questions
How do you identify yimengite?+
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What rocks look like yimengite?+
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Find yimengite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
