Matildite is a silver bismuth sulfide mineral frequently found in complex intergrowths with galena, often formed through the exsolution of silver-rich galena as it cools. Collectors typically find it as massive, metallic-gray blebs within sulfide ore deposits. It is best identified by its high density and metallic luster, often requiring microscopic examination to distinguish from associated sulfide species.
Is this matildite?
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 matildite with a known reference. Matildite sits at Mohs 2.5-3 — softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Matildite leaves a black streak.
- 3Read the lusterHold the specimen under a strong light. Matildite typically shows a metallic luster.
- 4Match the color rangeCompare against the expected color range: lead-gray, black.
- 5Look at form & habitCrystal system: trigonal. Typical habit: rarely as distinct crystals, usually massive or as intimate intergrowths with galena.
Often confused with
Matildite vs. its common look-alikes — and how to tell them apart in the field.
Often found alongside matildite
Minerals reported to co-occur with matildite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- AgBiS₂
- Mohs hardness
- 2.5-3
- Density
- 6.4-6.5 g/cm³
- Streak
- Black
- Luster
- Metallic
- Transparency
- Opaque
- Crystal system
- Trigonal
- Crystal habit
- Rarely as Distinct Crystals, Usually Massive or as Intimate Intergrowths with Galena
- Cleavage
- None
- Rarity
- Uncommon
- Uses
- Collector, Scientific Study
- Host rock
- Hydrothermal Veins
- Typical price
- $20-150 for small specimens
Where rockhounds find matildite
Classic worldwide localities
- Matildite locality, Peru
- Japan
- Germany
- USA
- Bolivia
Field-hunting tip
Look in hydrothermal veins country — that is the host setting where matildite typically forms. If you start seeing galena, bismuthinite, chalcopyrite in float, you are in the right ground. Field specimens usually show a rarely as distinct crystals, usually massive or as intimate intergrowths with galena habit, so train your eye for that shape before scanning the outcrop.
Common questions
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Find matildite on the map
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