Penobsquisite is an extremely rare borate mineral discovered in the potash mines of New Brunswick. It typically appears as small, colorless, tabular crystals found within evaporite sequences associated with other borate species.

Hardness

Mohs

Luster

Vitreous

Streak

White

Transparency

Transparent

mineralrare

Penobsquisite

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

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Is this penobsquisite?

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 penobsquisite with a known reference. Penobsquisite 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. Penobsquisite leaves a white streak.
3
Read the luster
Hold the specimen under a strong light. Penobsquisite 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.

Often found alongside penobsquisite

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

All properties

Chemical formula: Ca₂[B₉O₁₃(OH)₆]Cl·2H₂O
Mohs hardness: 2
Density: 1.79 g/cm³
Colors: Colorless White
Streak: White
Luster: Vitreous
Transparency: Transparent
Crystal system: Monoclinic
Crystal habit: Tabular Crystals
Cleavage: Perfect
Rarity: Rare
Uses: Collector
Host rock: Evaporite Deposits
Typical price: $50-300 per specimen

Where rockhounds find penobsquisite

Classic worldwide localities

Penobsquis, New Brunswick, Canada

Field-hunting tip

Look in evaporite deposits country — that is the host setting where penobsquisite typically forms. If you start seeing halite, sylvite, boracite in float, you are in the right ground. Field specimens usually show a tabular crystals habit, so train your eye for that shape before scanning the outcrop.

Common questions

How do you identify penobsquisite?+

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

Where is penobsquisite found?+

Notable localities include Penobsquis, New Brunswick, Canada.

How much is penobsquisite 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 minerals are found with penobsquisite?+

Penobsquisite commonly co-occurs with halite, sylvite, boracite. Spotting any of these in float or country rock is a useful trip signal.

What kind of rock does penobsquisite form in?+

Penobsquisite typically forms in evaporite deposits. Working float back to the host body is the standard way to chase a fresh occurrence.

What is penobsquisite used for?+

Penobsquisite is used in collector.

Find penobsquisite on the map

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