Paralstonite is a rare barium calcium carbonate mineral that is structurally related to alstonite. It is most famously found in the Illinois-Kentucky fluorspar district, often occurring as sharp, pseudo-hexagonal crystals embedded in or associated with fluorite.

Hardness

4-4.5

Mohs

Luster

Vitreous

Streak

White

Transparency

Transparent to translucent

mineralrareAlstonite-Paralstonite Group family

Paralstonite

Hardness: 4-4.5
Luster: Vitreous
Streak: White
Transparency: Transparent to translucent

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Is this paralstonite?

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 paralstonite with a known reference. Paralstonite sits at Mohs 4-4.5, softer than the next harder reference, harder than the previous one.
2
Check the streak
Drag the specimen across an unglazed porcelain plate. Streak: white.
3
Read the luster
Hold the specimen under a strong light. Luster: vitreous.
4
Match the color range
Compare against the expected color range: colorless, white.
5
Look at form & habit
Crystal system: trigonal. Typical habit: pseudo-hexagonal dipyramidal crystals.

Often confused with

Paralstonite vs. its common look-alikes, and how to tell them apart in the field.

Often found alongside paralstonite

Minerals reported to co-occur with paralstonite. Spotting these in float or country rock is a strong cue you are in the right ground.

All properties

Chemical formula: BaCa(CO₃)₂
Mohs hardness: 4-4.5
Density: 3.60 g/cm³
Colors: Colorless White
Streak: White
Luster: Vitreous
Transparency: Transparent to translucent
Crystal system: Trigonal
Crystal habit: Pseudo-hexagonal dipyramidal crystals
Cleavage: Distinct on {1011}
Fluorescence: Bright white/yellow under SW UV
Rarity: Rare
Uses: Collector
Host rock: A rare mineral in low-temperature hydrothermal Pb–Zn deposits

Where rockhounds find paralstonite

Classic worldwide localities

Minerva No. 1 and Annabel Lee mines, Cave-in-Rock, Hardin Co., Illinois, USA
Kedrovyi massif, five km southeast of the Murun massif, Aldan Shield, Sakha, Russia

Field-hunting tip

Where it forms: A rare mineral in low-temperature hydrothermal Pb–Zn deposits. If you start seeing calcite, alstonite, fluorite in float, you are in the right ground. Typical habit: pseudo-hexagonal dipyramidal crystals. Train your eye for that shape before scanning the outcrop.

Common questions

How do you identify paralstonite?+

Mohs hardness is 4-4.5. Luster: vitreous. The streak is white. Common colors include colorless, white.

Where is paralstonite found?+

Notable localities include Minerva No. 1 and Annabel Lee mines, Cave-in-Rock, Hardin Co., Illinois, USA; Kedrovyi massif, five km southeast of the Murun massif, Aldan Shield, Sakha, Russia.

Is paralstonite safe to handle?+

Paralstonite contains soluble barium. Wash your hands afterwards, never grind or breathe the dust, and store it apart from specimens you handle often.

What rocks look like paralstonite?+

Paralstonite is most often confused with Alstonite, Barytocalcite, Witherite. A quick hardness test and a streak check separate the look-alikes faster than color alone.

What minerals are found with paralstonite?+

Paralstonite commonly co-occurs with Calcite, Alstonite, Fluorite, Sphalerite, Olekminskite, Barite. Spotting any of these in float or country rock is a useful trip signal.

What kind of rock does paralstonite form in?+

Where it forms: A rare mineral in low-temperature hydrothermal Pb–Zn deposits. Working float back to the host body is the standard way to chase a fresh occurrence.

What is paralstonite used for?+

Paralstonite is used in collector.

Find paralstonite on the map

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