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. Streak: greenish white.
- 3Read the lusterHold the specimen under a strong light. Luster: vitreous.
- 4Match the color rangeCompare against the expected color range: blue green, blue.
- 5Look at form & habitCrystal system: hexagonal. Typical habit: acicular, rosette, spherical.
Often confused with
Agardite-(Y) vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Streak differs, so Agardite-(Y) leaves greenish white, Mixite leaves pale bluish green.
How to tell apart: Agardite-(Y) is noticeably harder (Mohs 3-4 vs. ~2); streak differs, so Agardite-(Y) leaves greenish white, Zippeite leaves yellow white.
How to tell apart: Streak differs, so Agardite-(Y) leaves greenish white, Conichalcite leaves 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
- 3.61-3.72 g/cm³
- Colors
- Streak
- Greenish white
- Luster
- Vitreous
- Transparency
- Semitransparent
- Crystal system
- Hexagonal
- Crystal habit
- Acicular, rosette, spherical
- Cleavage
- None
- Rarity
- Rare
- Uses
- Collector
- Host rock
- In the oxidation zone of some copper deposits
Where rockhounds find agardite-(y)
Classic worldwide localities
- Tintic district, Juab Co., Utah, USA
- Mohawk mine, Clark Mountains, San Bernardino Co., California, USA
- Granite Gap, San Simon district, Hidalgo Co., New Mexico, USA
- Bou Skour mine, Djebel Sarhro, Morocco
- Mutoshi, Katanga Province, Congo (Shaba Province, Zaire)
- Luisito mine, Anora, Córdoba Province, Spain
Field-hunting tip
Where it forms: In the oxidation zone of some copper deposits. If you start seeing azurite, malachite, chrysocolla in float, you are in the right ground. Typical habit: acicular, rosette, spherical. Train your eye for that shape before scanning the outcrop.
Common questions
How do you identify agardite-(y)?+
Where is agardite-(y) found?+
Is agardite-(y) safe to handle?+
What rocks look like agardite-(y)?+
What minerals are found with agardite-(y)?+
What kind of rock does agardite-(y) form in?+
What is agardite-(y) used for?+
Find agardite-(y) on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
