Miargyrite is a rare silver-antimony sulfosalt known for its deep cherry-red streak when powdered, which helps distinguish it from similar-looking sulfosalts. It typically forms as dark, metallic-looking crystals in hydrothermal deposits, often alongside other silver minerals and sulfides.
Is this miargyrite?
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 miargyrite with a known reference. Miargyrite sits at Mohs 2.5, softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Streak: cherry-red.
- 3Read the lusterHold the specimen under a strong light. Luster: metallic adamantine.
- 4Match the color rangeCompare against the expected color range: steel gray, lead gray, blackish red, reddish gray.
- 5Look at form & habitCrystal system: monoclinic. Typical habit: disseminated, euhedral crystals, massive.
Often confused with
Miargyrite vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Streak differs, so Miargyrite leaves cherry-red, Pyrargyrite leaves purplish red; luster reads metallic adamantine on Miargyrite and adamantine on Pyrargyrite.
How to tell apart: Streak differs, so Miargyrite leaves cherry-red, Proustite leaves vermilion; luster reads metallic adamantine on Miargyrite and adamantine on Proustite.
How to tell apart: Streak differs, so Miargyrite leaves cherry-red, Tetrahedrite leaves black to brown.
Often found alongside miargyrite
Minerals reported to co-occur with miargyrite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- AgSbS₂
- Mohs hardness
- 2.5
- Density
- 5.25 g/cm³
- Colors
- Streak
- Cherry-red
- Luster
- Metallic adamantine
- Transparency
- Translucent
- Crystal system
- Monoclinic
- Crystal habit
- Disseminated, euhedral crystals, massive
- Cleavage
- Imperfect on {010}; rare on {100} and {101}
- Rarity
- Uncommon
- Uses
- Collector, Reference specimen
- Host rock
- In hydrothermal veins of low-temperature origin
Where rockhounds find miargyrite
Classic worldwide localities
- Silver City and Flint districts, Owyhee Co., Idaho, USA
- Kelly, Coyote and Santa Fe mines, in the Randsburg district, San Bernardino Co., California, USA
- Braünsdorf, near Freiberg, Saxony (type locality), Germany
- St. Andreasberg and Clausthal, in the Harz Mountains, Germany
- Příbram and Třebsko, Czech Republic
- Baia Sprie, Romania (formerly Felsőbánya, Hungary)
Field-hunting tip
Where it forms: In hydrothermal veins of low-temperature origin. If you start seeing baumstarkite, proustite, pyrargyrite in float, you are in the right ground. Typical habit: disseminated, euhedral crystals, massive. Train your eye for that shape before scanning the outcrop.
Common questions
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Find miargyrite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
