Agardite-(Y) is a rare secondary mineral typically found as delicate, acicular, needle-like crystals forming distinct yellow to greenish-yellow radiating tufts. It is most frequently encountered as a collector's mineral in the oxidized zones of copper-rich hydrothermal deposits where it often coats other minerals like malachite.
Is this agardite-(y)?
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 agardite-(y) with a known reference. Agardite-(Y) sits at Mohs 3-4 — softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Agardite-(Y) leaves a white streak.
- 3Read the lusterHold the specimen under a strong light. Agardite-(Y) typically shows a vitreous luster.
- 4Match the color rangeCompare against the expected color range: yellow, greenish-yellow, pale green.
- 5Look at form & habitCrystal system: hexagonal. Typical habit: acicular or fibrous radial sprays and tufts.
Often confused with
Agardite-(Y) vs. its common look-alikes — and how to tell them apart in the field.
How to tell apart: Agardite-(Y) is noticeably harder (Mohs 3-4 vs. 2); streak differs — Agardite-(Y) leaves white, Zippeite leaves yellow; luster reads vitreous on Agardite-(Y) and pearly on Zippeite.
How to tell apart: Streak differs — Agardite-(Y) leaves white, Conichalcite leaves light green.
Often found alongside agardite-(y)
Minerals reported to co-occur with agardite-(y). Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- YCu₆(AsO₄)₃(OH)₆·3H₂O
- Mohs hardness
- 3-4
- Density
- 3.8-4.0 g/cm³
- Streak
- White
- Luster
- Vitreous
- Transparency
- Translucent
- Crystal system
- Hexagonal
- Crystal habit
- Acicular or Fibrous Radial Sprays and Tufts
- Cleavage
- None
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Oxidized Zones of Copper-arsenic Hydrothermal Deposits
- Typical price
- $20-150 for micro-mounts or small thumbnails
Where rockhounds find agardite-(y)
Classic worldwide localities
- Bou Skour mine, Morocco
- Tsumeb, Namibia
- Laurion, Greece
- Gold Hill, Utah, USA
Field-hunting tip
Look in oxidized zones of copper-arsenic hydrothermal deposits country — that is the host setting where agardite-(y) typically forms. If you start seeing malachite, azurite, olivenite in float, you are in the right ground. Field specimens usually show a acicular or fibrous radial sprays and tufts habit, so train your eye for that shape before scanning the outcrop.
Common questions
How do you identify agardite-(y)?+
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Is agardite-(y) safe to handle?+
What rocks look like agardite-(y)?+
What minerals are found with agardite-(y)?+
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Find agardite-(y) on the map
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