Maricopaite is a rare lead-calcium silicate often found as delicate, white, radiating sprays of needle-like crystals. It is primarily known from the Hilltop Mine in Arizona, where it occurs as a secondary mineral in oxidized ore zones.
Is this maricopaite?
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 maricopaite with a known reference. Maricopaite sits at Mohs 1-1.5, softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Streak: white.
- 3Read the lusterHold the specimen under a strong light. Luster: silky to vitreous.
- 4Match the color rangeCompare against the expected color range: white.
- 5Look at form & habitCrystal system: orthorhombic. Typical habit: radial.
Often confused with
Maricopaite vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Mimetite is the harder of the two (Mohs 3.5-4 vs. 1-1.5); luster reads silky to vitreous on Maricopaite and resinous to subadamantine on Mimetite.
How to tell apart: Cerussite is the harder of the two (Mohs 3-3.5 vs. 1-1.5); luster reads silky to vitreous on Maricopaite and adamantine, tending toward vitreous, resinous on Cerussite.
Often found alongside maricopaite
Minerals reported to co-occur with maricopaite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Ca₂Pb₇(Si₃₆Al₁₂)O₉₉·n(H₂O,OH)
- Mohs hardness
- 1-1.5
- Density
- 2.94 g/cm³
- Colors
- Streak
- White
- Luster
- Silky to vitreous
- Transparency
- Translucent to transparent
- Crystal system
- Orthorhombic
- Crystal habit
- Radial
- Cleavage
- {010}, imperfect
- Rarity
- Rare
- Uses
- Collector
- Host rock
- In a hydrothermal Pb-Cu ore vein, coating and filling fractures in quartz
Where rockhounds find maricopaite
Classic worldwide localities
- Moon Anchor mine, near Tonopah, Maricopa Co., Arizona, USA
Field-hunting tip
Where it forms: In a hydrothermal Pb-Cu ore vein, coating and filling fractures in quartz. If you start seeing cerussite, mimetite, fornacite in float, you are in the right ground. Typical habit: radial. Train your eye for that shape before scanning the outcrop.
Common questions
How do you identify maricopaite?+
Where is maricopaite found?+
Is maricopaite safe to handle?+
What rocks look like maricopaite?+
What minerals are found with maricopaite?+
What kind of rock does maricopaite form in?+
What is maricopaite used for?+
Find maricopaite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
