Pringleite is an extremely rare calcium borate mineral found almost exclusively in the potash-bearing evaporite deposits of New Brunswick, Canada. It typically forms small, pale yellow to brownish tabular crystals associated with other evaporite minerals like halite and sylvite.

Hardness

3-4

Mohs

Luster

Vitreous

Streak

White

Transparency

Transparent to translucent

mineralrare

Pringleite

Hardness: 3-4
Luster: Vitreous
Streak: White
Transparency: Transparent to translucent

Is this pringleite?

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 pringleite with a known reference. Pringleite sits at Mohs 3-4, 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, light yellow, orange.
5
Look at form & habit
Crystal system: triclinic. Typical habit: tabular crystals.

Often confused with

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

mineral

Boracite

Mohs 7-7.5

How to tell apart: Boracite is the harder of the two (Mohs 7-7.5 vs. 3-4).

Compare →

Often found alongside pringleite

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

All properties

Chemical formula: Ca₉B₂₆O₃₄(OH)₂₄Cl₄(H₂O)₁₀·3H₂O
Mohs hardness: 3-4
Density: 2.22 g/cm³
Colors: Colorless Light yellow Orange
Streak: White
Luster: Vitreous
Transparency: Transparent to translucent
Crystal system: Triclinic
Crystal habit: Tabular crystals
Cleavage: On {110}, good
Rarity: Rare
Uses: Collector
Host rock: Rare, in an evaporite deposit

Where rockhounds find pringleite

Classic worldwide localities

Potash Corporation of America mine, Penobsquis evaporite deposit, near Sussex, New Brunswick, Canada

Field-hunting tip

Where it forms: Rare, in an evaporite deposit. If you start seeing halite, ruitenbergite, sylvite in float, you are in the right ground. Typical habit: tabular crystals. Train your eye for that shape before scanning the outcrop.

Common questions

How do you identify pringleite?+

Mohs hardness is 3-4. Luster: vitreous. The streak is white. Common colors include colorless, light yellow, orange.

Where is pringleite found?+

Notable localities include Potash Corporation of America mine, Penobsquis evaporite deposit, near Sussex, New Brunswick, Canada.

What rocks look like pringleite?+

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

What minerals are found with pringleite?+

Pringleite commonly co-occurs with Halite, Ruitenbergite, Sylvite, Anhydrite, Quartz, Clays. Spotting any of these in float or country rock is a useful trip signal.

What kind of rock does pringleite form in?+

Where it forms: Rare, in an evaporite deposit. Working float back to the host body is the standard way to chase a fresh occurrence.

What is pringleite used for?+

Pringleite is used in collector.

Find pringleite on the map

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