Kellyite is a rare manganese-rich member of the serpentine group. It typically appears as yellowish-green micaceous or platy aggregates found within metamorphic manganese ore bodies.
Is this kellyite?
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 kellyite with a known reference. Kellyite sits at Mohs 2.5, softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Streak: yellowish white.
- 3Read the lusterHold the specimen under a strong light. Luster: vitreous to resinous.
- 4Match the color rangeCompare against the expected color range: golden yellow, lemon yellow.
- 5Look at form & habitCrystal system: hexagonal. Typical habit: lath, micaceous, tabular.
Often confused with
Kellyite vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Streak differs, so Kellyite leaves yellowish white, Chamosite leaves green to gray; luster reads vitreous to resinous on Kellyite and pearly on Chamosite.
How to tell apart: Streak differs, so Kellyite leaves yellowish white, Clinochlore leaves greenish white to white; luster reads vitreous to resinous on Kellyite and pearly, greasy, dull on Clinochlore.
Often found alongside kellyite
Minerals reported to co-occur with kellyite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- (Mn²⁺,Mg,Al)₆(Si,Al)₄O₁₀(OH)₈
- Mohs hardness
- 2.5
- Density
- 3.07 g/cm³
- Streak
- Yellowish white
- Luster
- Vitreous to resinous
- Transparency
- Transparent
- Crystal system
- Hexagonal
- Crystal habit
- Lath, micaceous, tabular
- Cleavage
- Perfect on {0001}
- Rarity
- Rare
- Uses
- Collector
- Host rock
- In banded Ca-Mn carbonate-rich rocks (Bald Knob mine, North Carolina, USA); in an intrusive alkalic gabbro-syenite complex (Mont Saint-Hilaire, Canada)
Where rockhounds find kellyite
Classic worldwide localities
- Bald Knob mine, near Sparta, Alleghany Co., North Carolina, USA
- Mont Saint-Hilaire, Quebec, Canada
Field-hunting tip
Where it forms: In banded Ca-Mn carbonate-rich rocks (Bald Knob mine, North Carolina, USA); in an intrusive alkalic gabbro-syenite complex (Mont Saint-Hilaire, Canada). If you start seeing kutnohorite, galaxite, jacobsite in float, you are in the right ground. Typical habit: lath, micaceous, tabular. Train your eye for that shape before scanning the outcrop.
Common questions
How do you identify kellyite?+
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What rocks look like kellyite?+
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Find kellyite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
