Stibarsen is a rare arsenic-antimony alloy that usually occurs as massive, botryoidal, or reniform aggregates with a metallic tin-white luster. It is typically found in hydrothermal veins associated with other arsenic minerals and is known historically by the name Allemontite. Collectors should exercise caution due to its significant arsenic content.
Is this stibarsen?
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 stibarsen with a known reference. Stibarsen sits at Mohs 3-4, softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Streak: gray.
- 3Read the lusterHold the specimen under a strong light. Luster: metallic, may be splendent, but not uncommonly dull.
- 4Match the color rangeCompare against the expected color range: white, gray, grayish white, reddish white.
- 5Look at form & habitCrystal system: trigonal. Typical habit: reniform.
Often confused with
Stibarsen vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Streak differs, so Stibarsen leaves gray, Arsenic leaves tin-white; luster reads metallic, may be splendent, but not uncommonly dull on Stibarsen and nearly metallic on Arsenic.
How to tell apart: Stibarsen is noticeably harder (Mohs 3-4 vs. 2); streak differs, so Stibarsen leaves gray, Stibnite leaves lead-gray.
How to tell apart: Streak differs, so Stibarsen leaves gray, Bismuth leaves pale silver.
Often found alongside stibarsen
Minerals reported to co-occur with stibarsen. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- AsSb
- Mohs hardness
- 3-4
- Density
- 5.8-6.2 g/cm³
- Streak
- Gray
- Luster
- Metallic, may be splendent, but not uncommonly dull
- Transparency
- Opaque
- Crystal system
- Trigonal
- Crystal habit
- Reniform
- Cleavage
- Perfect in one direction
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Most commonly in hydrothermal veins, but also in pegmatites
Where rockhounds find stibarsen
Classic worldwide localities
- Ophir mine, Comstock Lode, Virginia City, Storey Co., Nevada, USA
- Varuträsk pegmatite, 15 km northwest of Skellefteå, Västerbotten, Sweden (type locality)
- Marienberg, Saxony, and from St. Andreasberg, Harz Mountains, Germany
- Chalanches mine, near Allemont, Isère, France
- Cavnic (Kapnikbánya) and Baia Mare (Nagybánya), Romania
- Příbram, Czech Republic
Field-hunting tip
Where it forms: Most commonly in hydrothermal veins, but also in pegmatites. If you start seeing arsenic, arsenolite, antimony in float, you are in the right ground. Typical habit: reniform. Train your eye for that shape before scanning the outcrop.
Common questions
How do you identify stibarsen?+
Where is stibarsen found?+
Is stibarsen safe to handle?+
What rocks look like stibarsen?+
What minerals are found with stibarsen?+
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Find stibarsen on the map
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