Stibiconite is a secondary mineral commonly formed by the alteration of stibnite in oxidation zones of antimony deposits. It is frequently found as yellow, earthy crusts or pseudomorphs, retaining the original prismatic shape of the stibnite crystals it replaces.
Is this stibiconite?
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 stibiconite with a known reference. Stibiconite sits at Mohs 5.5-7, softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Streak: light yellow.
- 3Read the lusterHold the specimen under a strong light. Luster: pearly, opaline, glassy to earthy.
- 4Match the color rangeCompare against the expected color range: brown, gray, lemon white, light yellow, orange brown.
- 5Look at form & habitCrystal system: cubic. Typical habit: earthy, encrustations.
Often confused with
Stibiconite vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Stibiconite is noticeably harder (Mohs 5.5-7 vs. 4-4.5); streak differs, so Stibiconite leaves light yellow, Bindheimite leaves white, yellowish white; luster reads pearly, opaline, glassy to earthy on Stibiconite and resinous, dull, earthy on Bindheimite.
How to tell apart: Stibiconite is noticeably harder (Mohs 5.5-7 vs. 1-1.5); streak differs, so Stibiconite leaves light yellow, Kermesite leaves brownish red; luster reads pearly, opaline, glassy to earthy on Stibiconite and adamantine to semimetallic on Kermesite.
Often found alongside stibiconite
Minerals reported to co-occur with stibiconite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Sb³⁺Sb⁵⁺₂O₆(OH)
- Mohs hardness
- 5.5-7
- Density
- 5.3-5.6 g/cm³
- Colors
- Streak
- Light yellow
- Luster
- Pearly, opaline, glassy to earthy
- Transparency
- Transparent to translucent
- Crystal system
- Cubic
- Crystal habit
- Earthy, encrustations
- Cleavage
- None
- Rarity
- Common
- Uses
- Collector, Ore of antimony
- Host rock
- A secondary mineral in hydrothermal mineral deposits, formed by the oxidation of other antimony-bearing minerals, commonly stibnite, which it may entirely replace
Where rockhounds find stibiconite
Classic worldwide localities
- Black Warrior mine, near Unionville, Pershing Co., Nevada, USA
- Antimony, Garfield Co., Utah, USA
- Stanley stibnite mine, Shoshone Co., Idaho, USA
- Erskine Creek, Kern Co., California, USA
- Losacio, Zamora Province, Spain
- Ramsbeck, North Rhein-Westphalia, and in the Clara Mine, near Oberwolfach, Black Forest, Germany
Field-hunting tip
Where it forms: A secondary mineral in hydrothermal mineral deposits, formed by the oxidation of other antimony-bearing minerals, commonly stibnite, which it may entirely replace. If you start seeing cervantite, valentinite, kermesite in float, you are in the right ground. Typical habit: earthy, encrustations. Train your eye for that shape before scanning the outcrop.
Common questions
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Find stibiconite on the map
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