Gordaite is a rare secondary mineral typically found as delicate, pearly-white to pale-blue tabular crystals or micaceous aggregates. It is most notable for forming in the oxidation zones of zinc-rich base metal deposits, where it is often associated with other rare secondary copper and zinc species.
Is this gordaite?
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 gordaite with a known reference. Gordaite 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. Streak: white.
- 3Read the lusterHold the specimen under a strong light. Luster: vitreous to pearly.
- 4Match the color rangeCompare against the expected color range: white, colorless.
- 5Look at form & habitCrystal system: trigonal. Typical habit: massive, platy.
Often confused with
Gordaite vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Streak differs, so Gordaite leaves white, Namuwite leaves very pale green; luster reads vitreous to pearly on Gordaite and pearly on Namuwite.
How to tell apart: Luster reads vitreous to pearly on Gordaite and pearly, silky to dull or earthy in aggregates on Hydrozincite.
Often found alongside gordaite
Minerals reported to co-occur with gordaite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- NaZn₄(SO₄)(OH)₆Cl·6H₂O
- Mohs hardness
- 2.5
- Density
- 2.627 g/cm³
- Streak
- White
- Luster
- Vitreous to pearly
- Transparency
- Transparent to translucent
- Crystal system
- Trigonal
- Crystal habit
- Massive, platy
- Cleavage
- On {0001}, perfect
- Rarity
- Rare
- Uses
- Collector
- Host rock
- In the oxidized portions of a Cu-Zn sulfide deposit (San Francisco mine, Chile); on weathered mine dumps (Helbra, Germany)
Where rockhounds find gordaite
Classic worldwide localities
- San Francisco mine, two km west of the Sierra Gorda railway station, Sierra Gorda district, Antofagasta, Chile
- Juan de Fuca Ridge, southwest of Vancouver Island, Canada
- Helbra, Mansfeld region, Saxony-Anhalt, Germany
- Kamariza mine, Laurium, Greece
Field-hunting tip
Where it forms: In the oxidized portions of a Cu-Zn sulfide deposit (San Francisco mine, Chile); on weathered mine dumps (Helbra, Germany). If you start seeing zincian paratacamite, anglesite, hemimorphite in float, you are in the right ground. Typical habit: massive, platy. Train your eye for that shape before scanning the outcrop.
Common questions
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Is gordaite safe to handle?+
What rocks look like gordaite?+
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Find gordaite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
