Mcgovernite is a rare manganese zinc arsenate-silicate mineral known primarily from the unique ore deposits of Franklin and Sterling Hill, New Jersey. It typically occurs as bronze-colored foliated or tabular crystals associated with other rare zinc minerals.
Is this mcgovernite?
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 mcgovernite with a known reference. Mcgovernite 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. Mcgovernite leaves a yellowish streak.
- 3Read the lusterHold the specimen under a strong light. Mcgovernite typically shows a pearly luster.
- 4Match the color rangeCompare against the expected color range: bronze-brown, yellow-brown, orange-brown.
- 5Look at form & habitCrystal system: trigonal. Typical habit: tabular crystals, foliated, massive.
Often confused with
Mcgovernite vs. its common look-alikes — and how to tell them apart in the field.
How to tell apart: Friedelite is the harder of the two (Mohs 4-5 vs. 2.5); streak differs — Mcgovernite leaves yellowish, Friedelite leaves white; luster reads pearly on Mcgovernite and vitreous on Friedelite.
How to tell apart: Streak differs — Mcgovernite leaves yellowish, Dixenite leaves brownish-red; luster reads pearly on Mcgovernite and vitreous on Dixenite.
Often found alongside mcgovernite
Minerals reported to co-occur with mcgovernite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Mn²⁺₈Zn₂As³⁺₂(As⁵⁺O₄)₂(SiO₄)₂(OH)₁₀
- Mohs hardness
- 2.5
- Density
- 3.72 g/cm³
- Streak
- Yellowish
- Luster
- Pearly
- Transparency
- Translucent
- Crystal system
- Trigonal
- Crystal habit
- Tabular Crystals, Foliated, Massive
- Cleavage
- Perfect Basal
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Metamorphosed Zinc Ore Deposits
- Typical price
- $50-500 depending on specimen size and quality
Where rockhounds find mcgovernite
Classic worldwide localities
- Sterling Hill Mine, New Jersey, USA
- Franklin Mine, New Jersey, USA
Field-hunting tip
Look in metamorphosed zinc ore deposits country — that is the host setting where mcgovernite typically forms. If you start seeing willemite, zincite, franklinite in float, you are in the right ground. Field specimens usually show a tabular crystals, foliated, massive habit, so train your eye for that shape before scanning the outcrop.
Common questions
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Find mcgovernite on the map
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