Schöllhornite is a very rare hydrated sodium sulfide mineral first described from fumarolic deposits on the Tolbachik volcano in Russia. It typically occurs as small, delicate gray platy crystals that are highly sensitive to moisture and must be stored in sealed containers to prevent dehydration.
Is this schöllhornite?
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 schöllhornite with a known reference. Schöllhornite sits at Mohs 1.5-2, softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Streak: yellow.
- 3Read the lusterHold the specimen under a strong light. Luster: submetallic (synthetic).
- 4Match the color rangeCompare against the expected color range: gray.
- 5Look at form & habitCrystal system: trigonal. Typical habit: microscopic crystals.
Often confused with
Schöllhornite vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Streak differs, so Schöllhornite leaves yellow, Jarosite leaves pale yellow; luster reads submetallic (synthetic) on Schöllhornite and subadamantine to vitreous, resinous on fractures on Jarosite.
How to tell apart: Natrojarosite is the harder of the two (Mohs 3 vs. 1.5-2); streak differs, so Schöllhornite leaves yellow, Natrojarosite leaves light yellow; luster reads submetallic (synthetic) on Schöllhornite and vitreous on Natrojarosite.
Often found alongside schöllhornite
Minerals reported to co-occur with schöllhornite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Na₀.₃CrS₂(H₂O)
- Mohs hardness
- 1.5-2
- Density
- 2.70 g/cm³
- Colors
- Streak
- Yellow
- Luster
- Submetallic (synthetic)
- Transparency
- Opaque
- Crystal system
- Trigonal
- Crystal habit
- Microscopic crystals
- Cleavage
- Perfect on {0001}
- Rarity
- Rare
- Uses
- Collector
- Host rock
- In an enstatite achondrite meteorite with other chromium-rich minerals, probably formed by terrestrial weathering of caswellsilverite
Where rockhounds find schöllhornite
Classic worldwide localities
- Waethering product of caswellsilverite in the Norton County enstatite achondrite (type locality)
Field-hunting tip
Where it forms: In an enstatite achondrite meteorite with other chromium-rich minerals, probably formed by terrestrial weathering of caswellsilverite. If you start seeing caswellsilverite, daubréelite, titanoan troilite in float, you are in the right ground. Typical habit: microscopic crystals. Train your eye for that shape before scanning the outcrop.
Common questions
How do you identify schöllhornite?+
Where is schöllhornite found?+
What rocks look like schöllhornite?+
What minerals are found with schöllhornite?+
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What is schöllhornite used for?+
Find schöllhornite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
