Glaucochroite is a rare calcium-manganese silicate member of the olivine group primarily known from the historic zinc mines of Franklin and Sterling Hill, New Jersey. It typically occurs as prismatic to tabular crystals associated with franklinite and willemite in metamorphosed ore bodies. Collectors look for its characteristic pink to pale brownish hues and its distinct association with other unique zinc-manganese species.
Is this glaucochroite?
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 glaucochroite with a known reference. Glaucochroite sits at Mohs 6 — softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Glaucochroite leaves a white streak.
- 3Read the lusterHold the specimen under a strong light. Glaucochroite typically shows a vitreous luster.
- 4Match the color rangeCompare against the expected color range: pink, pale brown, colorless.
- 5Look at form & habitCrystal system: orthorhombic. Typical habit: prismatic to tabular crystals.
Often confused with
Glaucochroite vs. its common look-alikes — and how to tell them apart in the field.
Often found alongside glaucochroite
Minerals reported to co-occur with glaucochroite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- CaMnSiO₄
- Mohs hardness
- 6
- Density
- 3.41 g/cm³
- Colors
- Streak
- White
- Luster
- Vitreous
- Transparency
- Translucent
- Crystal system
- Orthorhombic
- Crystal habit
- Prismatic to Tabular Crystals
- Cleavage
- Distinct On {010}
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Metamorphosed Zinc Ore Deposits
- Typical price
- $50-500 thumbnail size depending on quality
Where rockhounds find glaucochroite
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 glaucochroite typically forms. If you start seeing willemite, franklinite, zincite 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 glaucochroite on the map
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