Hauckite is a very rare hydrated iron-zinc sulfate mineral typically found as small, yellow, micaceous hexagonal plates. It is almost exclusively known from the Franklin and Sterling Hill mines in New Jersey, where it occurs in association with other zinc-rich minerals in metamorphosed deposits.
Is this hauckite?
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 hauckite with a known reference. Hauckite sits at Mohs 2-3, softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Streak: yellow to pale yellow.
- 3Read the lusterHold the specimen under a strong light. Luster: vitreous to slightly pearly.
- 4Match the color rangeCompare against the expected color range: bright orange, light yellow.
- 5Look at form & habitCrystal system: hexagonal. Typical habit: platy.
Often confused with
Hauckite vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Streak differs, so Hauckite leaves yellow to pale yellow, Woodwardite leaves light blue; luster reads vitreous to slightly pearly on Hauckite and pearly on Woodwardite.
How to tell apart: Streak differs, so Hauckite leaves yellow to pale yellow, Hydrotalcite leaves white; luster reads vitreous to slightly pearly on Hauckite and satiny to greasy or waxy on Hydrotalcite.
Often found alongside hauckite
Minerals reported to co-occur with hauckite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Fe₃Mg₂₄Zn₁₈(SO₄)₄(CO₃)₂(OH)₈₁
- Mohs hardness
- 2-3
- Density
- 3.02 g/cm³
- Streak
- Yellow to pale yellow
- Luster
- Vitreous to slightly pearly
- Transparency
- Semitransparent
- Crystal system
- Hexagonal
- Crystal habit
- Platy
- Cleavage
- On {0001}, perfect
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Very rare, found in several different parageneses in a metamorphosed stratiform zinc orebody
Where rockhounds find hauckite
Classic worldwide localities
- Sterling Hill, Ogdensburg, Sussex Co., New Jersey, USA
Field-hunting tip
Where it forms: Very rare, found in several different parageneses in a metamorphosed stratiform zinc orebody. If you start seeing mooreite, phlogopite, calcite in float, you are in the right ground. Typical habit: platy. Train your eye for that shape before scanning the outcrop.
Common questions
How do you identify hauckite?+
Where is hauckite found?+
What rocks look like hauckite?+
What minerals are found with hauckite?+
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Find hauckite on the map
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