Köttigite is a rare secondary zinc arsenate mineral that typically forms white to colorless prismatic crystals or crusts. It is most commonly found in the oxidation zones of arsenic-rich zinc deposits and is prized by mineral collectors for its distinct, intense coloration.
Is this köttigite?
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 köttigite with a known reference. Köttigite 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: white to reddish white.
- 3Read the lusterHold the specimen under a strong light. Luster: silky on cleavages.
- 4Match the color rangeCompare against the expected color range: red, brownish.
- 5Look at form & habitCrystal system: monoclinic. Typical habit: encrustations, massive, prismatic.
Often confused with
Köttigite vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Luster reads silky on cleavages on Köttigite and vitreous, pearly on the cleavage, dull when earthy on Vivianite.
How to tell apart: Streak differs, so Köttigite leaves white to reddish white, Erythrite leaves pale red to pink; luster reads silky on cleavages on Köttigite and subadamantine, pearly on cleavages on Erythrite.
Often found alongside köttigite
Minerals reported to co-occur with köttigite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Zn₃(AsO₄)₂·8H₂O
- Mohs hardness
- 2-3
- Density
- 3.33 g/cm³
- Streak
- White to reddish white
- Luster
- Silky on cleavages
- Transparency
- Translucent
- Crystal system
- Monoclinic
- Crystal habit
- Encrustations, massive, prismatic
- Cleavage
- On {010}, perfect
- Rarity
- Rare
- Uses
- Collector
- Host rock
- A rare secondary mineral in the oxidation zone of some zinc deposits
Where rockhounds find köttigite
Classic worldwide localities
- Sterling Hill, Ogdensburg, Sussex Co., New Jersey, and in the Clan Alpine Mountains, east side of Stingaree Valley, Churchill Co., Nevada, USA
- Daniel mine, Schneeberg, Saxony, Germany
- Richelsdorf Mountains, Hesse, Germany
- Michael mine, Weiler, near Lahr, and the Clara mine, near Oberwolfach, Black Forest, Germany
- Jáchymov (Joachimsthal) and Příbram, Czech Republic
- Ojuela mine, Mapimí, Durango, Mexico
Field-hunting tip
Where it forms: A rare secondary mineral in the oxidation zone of some zinc deposits. If you start seeing symplesite, parasymplesite, adamite in float, you are in the right ground. Typical habit: encrustations, massive, prismatic. Train your eye for that shape before scanning the outcrop.
Common questions
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Find köttigite on the map
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