Parnauite is a rare secondary copper arsenate-sulfate mineral that forms distinctive acicular to bladed crystal sprays. Collectors typically find it as vibrant blue to greenish-blue crusts or small radial clusters within the oxidized zones of copper-rich hydrothermal ore deposits.
Is this parnauite?
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 parnauite with a known reference. Parnauite 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. Parnauite leaves a pale blue streak.
- 3Read the lusterHold the specimen under a strong light. Parnauite typically shows a vitreous luster.
- 4Match the color rangeCompare against the expected color range: blue, greenish-blue, emerald-green.
- 5Look at form & habitCrystal system: orthorhombic. Typical habit: acicular or bladed crystals, also in radial clusters or crusts.
Often confused with
Parnauite vs. its common look-alikes — and how to tell them apart in the field.
Often found alongside parnauite
Minerals reported to co-occur with parnauite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Cu₉(AsO₄)₂SO₄(OH)₁₀·7H₂O
- Mohs hardness
- 2.5
- Density
- 3.8-3.9 g/cm³
- Streak
- Pale Blue
- Luster
- Vitreous
- Transparency
- Translucent
- Crystal system
- Orthorhombic
- Crystal habit
- Acicular or Bladed Crystals, Also in Radial Clusters or Crusts
- Cleavage
- Distinct
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Oxidized Zones of Copper-arsenic Deposits
- Typical price
- $50-300 per specimen
Where rockhounds find parnauite
Classic worldwide localities
- Majuba Hill Mine, Nevada, USA
- Tintic District, Utah, USA
- Cap Garonne, France
- Gunnison County, Colorado, USA
Field-hunting tip
Look in oxidized zones of copper-arsenic deposits country — that is the host setting where parnauite typically forms. If you start seeing clinoclase, cornubite, olivenite in float, you are in the right ground. Field specimens usually show a acicular or bladed crystals, also in radial clusters or crusts habit, so train your eye for that shape before scanning the outcrop.
Common questions
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Find parnauite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
