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 — Macquartite leaves yellow, Vauquelinite leaves greenish-yellow; luster reads vitreous on Macquartite and resinous to adamantine on Vauquelinite.
How to tell apart: Streak differs — 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 — that is 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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