Hancockite is a rare lead-bearing member of the epidote group typically found in the famous zinc-manganese orebodies of Franklin and Sterling Hill. Collectors look for its distinctive deep reddish-brown tabular crystals that often display a subtle, vitreous luster.
Is this hancockite?
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 hancockite with a known reference. Hancockite sits at Mohs 6-7 — softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Hancockite leaves a light brown streak.
- 3Read the lusterHold the specimen under a strong light. Hancockite typically shows a vitreous luster.
- 4Match the color rangeCompare against the expected color range: reddish-brown, brown, black.
- 5Look at form & habitCrystal system: monoclinic. Typical habit: prismatic to tabular crystals.
Often confused with
Hancockite vs. its common look-alikes — and how to tell them apart in the field.
How to tell apart: Streak differs — Hancockite leaves light brown, Epidote leaves white.
How to tell apart: Streak differs — Hancockite leaves light brown, Allanite leaves gray; luster reads vitreous on Hancockite and submetallic on Allanite.
How to tell apart: Streak differs — Hancockite leaves light brown, Clinozoisite leaves white.
Often found alongside hancockite
Minerals reported to co-occur with hancockite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- (Pb,Ca,Sr)₂ (Al,Fe,Mn)₃ (Si₂O₇)(SiO₄)O(OH)
- Mohs hardness
- 6-7
- Density
- 4.05 g/cm³
- Colors
- Streak
- Light Brown
- Luster
- Vitreous
- Transparency
- Translucent
- Crystal system
- Monoclinic
- Crystal habit
- Prismatic to Tabular Crystals
- Cleavage
- Distinct On One Face
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Metamorphosed Zinc Ore Deposits
- Typical price
- $50-500 depending on crystal size and quality
Where rockhounds find hancockite
Classic worldwide localities
- Franklin, New Jersey, USA
- Sterling Hill, New Jersey, USA
Field-hunting tip
Look in metamorphosed zinc ore deposits country — that is the host setting where hancockite typically forms. If you start seeing willemite, franklinite, andradite in float, you are in the right ground. Field specimens usually show a prismatic to tabular crystals habit, so train your eye for that shape before scanning the outcrop.
Common questions
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Find hancockite on the map
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