Orschallite is an extremely rare calcium sulfite mineral discovered in volcanic fumaroles. It typically forms as delicate tabular crystals or crusts alongside gypsum and elemental sulfur in high-temperature volcanic environments.
Is this orschallite?
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 orschallite with a known reference. Orschallite sits at Mohs ~4, softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Streak: white.
- 3Read the lusterHold the specimen under a strong light. Luster: vitreous.
- 4Match the color rangeCompare against the expected color range: colorless.
- 5Look at form & habitCrystal system: trigonal. Typical habit: tabular crystals, crusts.
Often confused with
Orschallite vs. its common look-alikes, and how to tell them apart in the field.
Often found alongside orschallite
Minerals reported to co-occur with orschallite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Ca₃(SO₃)₂SO₄(H₂O)₁₂
- Mohs hardness
- ~4
- Density
- 1.90 g/cm³
- Colors
- Streak
- White
- Luster
- Vitreous
- Transparency
- Transparent
- Crystal system
- Trigonal
- Crystal habit
- Tabular crystals, crusts
- Cleavage
- None
- Rarity
- Rare
- Uses
- Collector
- Host rock
- A rare species, an intermediate stage in oxidation of sulfides to sulfates, preserved in a melilite nepheline leucitite quenched during a submarine volcanic eruption
Where rockhounds find orschallite
Classic worldwide localities
- Hannebacher Ley volcano, one km east-northeast of Hannebach, Eifel, Germany
Field-hunting tip
Where it forms: A rare species, an intermediate stage in oxidation of sulfides to sulfates, preserved in a melilite nepheline leucitite quenched during a submarine volcanic eruption. If you start seeing clinopyroxene, apatite, phillipsite in float, you are in the right ground. Typical habit: tabular crystals, crusts. Train your eye for that shape before scanning the outcrop.
Common questions
How do you identify orschallite?+
Where is orschallite found?+
What rocks look like orschallite?+
What minerals are found with orschallite?+
What kind of rock does orschallite form in?+
What is orschallite used for?+
Find orschallite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
