Ziesite is a rare copper vanadate mineral typically found as a volcanic sublimates in fumarolic deposits. It is known for its distinctive yellow to orange color and often occurs as thin, platy crystals on volcanic rock surfaces.
Is this ziesite?
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 ziesite with a known reference. Ziesite sits at Mohs 3, softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Ziesite leaves a reddish brown streak.
- 3Read the lusterHold the specimen under a strong light. Ziesite typically shows a metallic luster.
- 4Match the color rangeCompare against the expected color range: black.
- 5Look at form & habitCrystal system: monoclinic. Typical habit: platy crystals, crusts.
Often confused with
Ziesite vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Streak differs, so Ziesite leaves reddish brown, Bloedite leaves white; luster reads metallic on Ziesite and vitreous on Bloedite.
How to tell apart: Streak differs, so Ziesite leaves reddish brown, Thénardite leaves white; luster reads metallic on Ziesite and vitreous on Thénardite.
Often found alongside ziesite
Minerals reported to co-occur with ziesite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Cu₂V₂O₇
- Mohs hardness
- 3
- Density
- 3.84 g/cm³
- Colors
- Streak
- Reddish Brown
- Luster
- Metallic
- Transparency
- Translucent
- Crystal system
- Monoclinic
- Crystal habit
- Platy Crystals, Crusts
- Cleavage
- Perfect
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Volcanic Fumaroles
Where rockhounds find ziesite
Classic worldwide localities
- Izalco Volcano, El Salvador
Field-hunting tip
Look in volcanic fumaroles country, the host setting where ziesite typically forms. If you start seeing thenardite, vanthoffite, bloedite in float, you are in the right ground. Field specimens usually show a platy crystals, crusts habit, so train your eye for that shape before scanning the outcrop.
Common questions
How do you identify ziesite?+
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Find ziesite on the map
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