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, 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.