Marcobaldiite is a rare lead-antimony sulfosalt known primarily from its type locality in the Apuan Alps of Italy. It typically forms as dark, lead-grey metallic tabular crystals found within hydrothermal vein deposits.
Is this marcobaldiite?
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 marcobaldiite with a known reference. Marcobaldiite 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. Marcobaldiite leaves a grey-black streak.
- 3Read the lusterHold the specimen under a strong light. Marcobaldiite typically shows a metallic luster.
- 4Match the color rangeCompare against the expected color range: dark gray, lead gray.
- 5Look at form & habitCrystal system: triclinic. Typical habit: tabular crystals.
Often confused with
Marcobaldiite vs. its common look-alikes — and how to tell them apart in the field.
How to tell apart: Streak differs — Marcobaldiite leaves grey-black, Galena leaves lead-gray.
How to tell apart: Streak differs — Marcobaldiite leaves grey-black, Jamesonite leaves gray-black.
How to tell apart: Streak differs — Marcobaldiite leaves grey-black, Bournonite leaves steel-gray.
Often found alongside marcobaldiite
Minerals reported to co-occur with marcobaldiite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Pb₄(Sb,As)₆S₁₃
- Mohs hardness
- 3
- Density
- 6.05 g/cm³
- Streak
- Grey-black
- Luster
- Metallic
- Transparency
- Opaque
- Crystal system
- Triclinic
- Crystal habit
- Tabular Crystals
- Cleavage
- Perfect
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Hydrothermal Veins
- Typical price
- $50-500 depending on specimen quality and size
Where rockhounds find marcobaldiite
Classic worldwide localities
- Buca della Vena mine, Italy
Field-hunting tip
Look in hydrothermal veins country — that is the host setting where marcobaldiite typically forms. If you start seeing galena, pyrite, sphalerite in float, you are in the right ground. Field specimens usually show a tabular crystals habit, so train your eye for that shape before scanning the outcrop.
Common questions
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Find marcobaldiite on the map
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