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. Streak: reddish brown.
- 3Read the lusterHold the specimen under a strong light. Luster: metallic.
- 4Match the color rangeCompare against the expected color range: black.
- 5Look at form & habitCrystal system: monoclinic. Typical habit: anhedral grains, microscopic crystals.
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, Blödite leaves white; luster reads metallic on Ziesite and vitreous on Blödite.
How to tell apart: Streak differs, so Ziesite leaves reddish brown, Thénardite leaves white; luster reads metallic on Ziesite and vitreous to resinous 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
- 3.86 g/cm³
- Colors
- Streak
- Reddish brown
- Luster
- Metallic
- Transparency
- Opaque, transparent on very thin edges
- Crystal system
- Monoclinic
- Crystal habit
- Anhedral grains, microscopic crystals
- Cleavage
- None
- Rarity
- Rare
- Uses
- Collector
- Host rock
- In vanadium-bearing sublimates in fumaroles on a basaltic volcanic cone
Where rockhounds find ziesite
Classic worldwide localities
- Izalco volcano, El Salvador (type locality)
Field-hunting tip
Where it forms: In vanadium-bearing sublimates in fumaroles on a basaltic volcanic cone. If you start seeing stoiberite, shcherbinaite, bannermanite in float, you are in the right ground. Typical habit: anhedral grains, microscopic crystals. Train your eye for that shape before scanning the outcrop.
Common questions
How do you identify ziesite?+
Where is ziesite found?+
Is ziesite safe to handle?+
What rocks look like ziesite?+
What minerals are found with ziesite?+
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Find ziesite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
