Apachite is a rare hydrous copper silicate mineral typically found as delicate, pale blue acicular or fibrous clusters. It is almost exclusively found in association with other copper minerals in the oxidized zones of copper deposits in Arizona. Collectors prize it for its unique, icy blue color and characteristic radial growth habits.
Is this apachite?
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 apachite with a known reference. Apachite sits at Mohs 2, softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Streak: light blue.
- 3Read the lusterHold the specimen under a strong light. Luster: nonmetallic, silky.
- 4Match the color rangeCompare against the expected color range: blue.
- 5Look at form & habitCrystal system: monoclinic. Typical habit: radial, spherical.
Often confused with
Apachite vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Streak differs, so Apachite leaves light blue, Chrysocolla leaves white when pure; luster reads nonmetallic, silky on Apachite and vitreous, porcelaneous, earthy on Chrysocolla.
How to tell apart: Shattuckite is the harder of the two (Mohs ~3.5 vs. 2); streak differs, so Apachite leaves light blue, Shattuckite leaves pale blue; luster reads nonmetallic, silky on Apachite and silky on Shattuckite.
How to tell apart: Planerite is the harder of the two (Mohs 5 vs. 2); streak differs, so Apachite leaves light blue, Planerite leaves blue white; luster reads nonmetallic, silky on Apachite and dull, chalky to earthy on Planerite.
Often found alongside apachite
Minerals reported to co-occur with apachite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Cu₉Si₁₀O₂₉·11H₂O
- Mohs hardness
- 2
- Density
- 2.80 g/cm³
- Colors
- Streak
- Light blue
- Luster
- Nonmetallic, silky
- Transparency
- Transparent to translucent
- Crystal system
- Monoclinic
- Crystal habit
- Radial, spherical
- Cleavage
- Perfect
- Rarity
- Rare
- Uses
- Collector
- Host rock
- A retrograde metamorphic or mesogene mineral, formed at the expense of a prograde calc-silicate and sulfide assemblage in tactites
Where rockhounds find apachite
Classic worldwide localities
- Christmas copper mine, Gila Co., Arizona, USA
Field-hunting tip
Where it forms: A retrograde metamorphic or mesogene mineral, formed at the expense of a prograde calc-silicate and sulfide assemblage in tactites. If you start seeing kinoite, gilalite, stringhamite in float, you are in the right ground. Typical habit: radial, spherical. Train your eye for that shape before scanning the outcrop.
Common questions
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Find apachite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
