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.

Hardness

Mohs

Luster

Vitreous

Streak

White

Transparency

Transparent

mineralrareSulfite minerals family

Orschallite

Hardness: 2
Luster: Vitreous
Streak: White
Transparency: Transparent

Is this orschallite?

5-step field check

Run through these checks against the specimen in your hand. The more boxes tick, the more confident the ID.

1
Test the hardness
Try to scratch orschallite with a known reference. Orschallite sits at Mohs 2 — softer than the next harder reference, harder than the previous one.
2
Check the streak
Drag the specimen across an unglazed porcelain plate. Orschallite leaves a white streak.
3
Read the luster
Hold the specimen under a strong light. Orschallite typically shows a vitreous luster.
4
Match the color range
Compare against the expected color range: colorless, white.
5
Look at form & habit
Crystal system: monoclinic. 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.

Gypsum
mineral · Mohs 2

All properties

Chemical formula: Ca₃(SO₃)₂·4H₂O
Mohs hardness: 2
Density: 2.35 g/cm³
Colors: Colorless White
Streak: White
Luster: Vitreous
Transparency: Transparent
Crystal system: Monoclinic
Crystal habit: Tabular Crystals, Crusts
Cleavage: Good
Rarity: Rare
Uses: Collector
Host rock: Volcanic Fumaroles
Typical price: $50-300 per specimen

Where rockhounds find orschallite

Classic worldwide localities

Etna volcano, Sicily, Italy

Field-hunting tip

Look in volcanic fumaroles country — that is the host setting where orschallite typically forms. If you start seeing gypsum, sulphur in float, you are in the right ground. Field specimens usually show a tabular crystals, crusts habit, so train your eye for that shape before scanning the outcrop.

Common questions

How do you identify orschallite?+

Mohs hardness is 2. It typically shows a vitreous luster. The streak is white. Common colors include colorless, white.

Where is orschallite found?+

Notable localities include Etna volcano, Sicily, Italy.

How much is orschallite worth?+

Typical asking prices fall in the range of $50-300 per specimen. Quality, size, and provenance can move individual specimens well outside that range.

What rocks look like orschallite?+

Orschallite is most often confused with Gypsum. A quick hardness test and a streak check separate the look-alikes faster than color alone.

What minerals are found with orschallite?+

Orschallite commonly co-occurs with Gypsum, Sulphur. Spotting any of these in float or country rock is a useful trip signal.

What kind of rock does orschallite form in?+

Orschallite typically forms in volcanic fumaroles. Working float back to the host body is the standard way to chase a fresh occurrence.

What is orschallite used for?+

Orschallite is used in collector.

Find orschallite on the map

RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.