Macquartite is a rare lead-copper chromate-silicate mineral typically found as bright yellow, needle-like acicular crystals. It is most famous for its occurrence at the Mammoth-Saint Anthony mine in Arizona, where it forms in the oxidized zones of copper-lead ore bodies. Collectors look for its distinctive yellow acicular clusters on matrix, often associated with other rare oxidation products.
Is this macquartite?
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 macquartite with a known reference. Macquartite 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. Macquartite leaves a yellow streak.
- 3Read the lusterHold the specimen under a strong light. Macquartite typically shows a vitreous luster.
- 4Match the color rangeCompare against the expected color range: yellow, greenish-yellow.
- 5Look at form & habitCrystal system: monoclinic. Typical habit: acicular or fibrous crystals.
Often confused with
Macquartite vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Streak differs, so Macquartite leaves yellow, Vauquelinite leaves greenish-yellow; luster reads vitreous on Macquartite and resinous to adamantine on Vauquelinite.
How to tell apart: Streak differs, so Macquartite leaves yellow, Phoenicochroite leaves orange-yellow; luster reads vitreous on Macquartite and adamantine on Phoenicochroite.
Often found alongside macquartite
Minerals reported to co-occur with macquartite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Pb₃Cu(CrO₄)SiO₃(OH)₂(H₂O)
- Mohs hardness
- 3
- Density
- 4.9 g/cm³
- Colors
- Streak
- Yellow
- Luster
- Vitreous
- Transparency
- Translucent
- Crystal system
- Monoclinic
- Crystal habit
- Acicular or Fibrous Crystals
- Cleavage
- Perfect On {100}
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Oxidized Zones of Hydrothermal Base Metal Deposits
- Typical price
- $50-500 thumbnail depending on quality and matrix
Where rockhounds find macquartite
Classic worldwide localities
- Mammoth-Saint Anthony mine, Tiger, Arizona, USA
Field-hunting tip
Look in oxidized zones of hydrothermal base metal deposits country, the host setting where macquartite typically forms. If you start seeing wulfenite, dioptase, cerussite in float, you are in the right ground. Field specimens usually show a acicular or fibrous crystals habit, so train your eye for that shape before scanning the outcrop.
Common questions
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Find macquartite on the map
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