Karenwebberite is a rare phosphate mineral member of the triplite group, characterized by its distinctive brown coloration and specific sodium-iron-fluorine chemistry. It is primarily found as anhedral grains within phosphate nodules located in the Big Fish River area of the Yukon, requiring laboratory identification to distinguish from similar species like triplite.
Is this karenwebberite?
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 karenwebberite with a known reference. Karenwebberite sits at Mohs 4.5, softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Streak: very pale grayish green.
- 3Read the lusterHold the specimen under a strong light. Luster: greasy to vitreous.
- 4Match the color rangeCompare against the expected color range: dark green, pale, brownish if oxidized.
- 5Look at form & habitCrystal system: orthorhombic. Typical habit: anhedral grains.
Often confused with
Karenwebberite vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Streak differs, so Karenwebberite leaves very pale grayish green, Triplite leaves white to brown; luster reads greasy to vitreous on Karenwebberite and vitreous to resinous on Triplite.
How to tell apart: Streak differs, so Karenwebberite leaves very pale grayish green, Wolfeite leaves white; luster reads greasy to vitreous on Karenwebberite and vitreous to silky if fibrous on Wolfeite.
Often found alongside karenwebberite
Minerals reported to co-occur with karenwebberite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- NaFe(PO₄)
- Mohs hardness
- 4.5
- Density
- 3.65 g/cm³
- Colors
- Streak
- Very pale grayish green
- Luster
- Greasy to vitreous
- Transparency
- Transparent to translucent
- Crystal system
- Orthorhombic
- Crystal habit
- Anhedral grains
- Cleavage
- Perfect on {001}
- Rarity
- Rare
- Uses
- Collector
- Host rock
- As late-magmatic exsolution lamellae hosted by graftonite in plagioclase within the central portion of a granitic pegmatite dike
Where rockhounds find karenwebberite
Classic worldwide localities
- Malpensata pegmatite dike, Colico commune, Lecco Province, Italy
Field-hunting tip
Where it forms: As late-magmatic exsolution lamellae hosted by graftonite in plagioclase within the central portion of a granitic pegmatite dike. If you start seeing graftonite, na-bearing ferrisicklerite in float, you are in the right ground. Typical habit: anhedral grains. Train your eye for that shape before scanning the outcrop.
Common questions
How do you identify karenwebberite?+
Where is karenwebberite found?+
What rocks look like karenwebberite?+
What minerals are found with karenwebberite?+
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Find karenwebberite on the map
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