Greenwoodite is an extremely rare lead-chromium silicate mineral that forms dark, platy crystals. It is primarily known from the Greenwood Mine in California and is highly prized by advanced mineral collectors due to its distinct composition and scarcity.
Is this greenwoodite?
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 greenwoodite with a known reference. Greenwoodite sits at Mohs 4 — softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Greenwoodite leaves a pale green streak.
- 3Read the lusterHold the specimen under a strong light. Greenwoodite typically shows a vitreous luster.
- 4Match the color rangeCompare against the expected color range: dark green, blackish-green.
- 5Look at form & habitCrystal system: trigonal. Typical habit: platy crystals.
Often confused with
Greenwoodite vs. its common look-alikes — and how to tell them apart in the field.
How to tell apart: Greenwoodite is noticeably harder (Mohs 4 vs. 2.5-3); streak differs — Greenwoodite leaves pale green, Crocoite leaves orange-yellow; luster reads vitreous on Greenwoodite and adamantine on Crocoite.
How to tell apart: Fayalite is the harder of the two (Mohs 6.5-7 vs. 4); streak differs — Greenwoodite leaves pale green, Fayalite leaves white.
Often found alongside greenwoodite
Minerals reported to co-occur with greenwoodite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- PbCr₂Fe₅Si₄O₁₈(OH)₂
- Mohs hardness
- 4
- Density
- 4.24 g/cm³
- Colors
- Streak
- Pale Green
- Luster
- Vitreous
- Transparency
- Translucent
- Crystal system
- Trigonal
- Crystal habit
- Platy Crystals
- Cleavage
- Perfect
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Hydrothermal Veins
- Typical price
- $100-500 for small specimens
Where rockhounds find greenwoodite
Classic worldwide localities
- Greenwood Mine, California, USA
Field-hunting tip
Look in hydrothermal veins country — that is the host setting where greenwoodite typically forms. If you start seeing quartz, galena, sphalerite in float, you are in the right ground. Field specimens usually show a platy crystals habit, so train your eye for that shape before scanning the outcrop.
Common questions
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Find greenwoodite on the map
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