Ruitenbergite is a rare calcium borate mineral known primarily from salt mine localities in New Brunswick, Canada. It typically forms as delicate, transparent to white bladed or tabular crystals within evaporite sequences.

Hardness

3-4

Mohs

Luster

Vitreous

Streak

White

Transparency

Transparent to translucent

mineralrareBorate Mineral family

Ruitenbergite

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

No image

Is this ruitenbergite?

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 ruitenbergite with a known reference. Ruitenbergite 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.
5
Look at form & habit
Crystal system: monoclinic. Typical habit: bladed to tabular crystals.

Often confused with

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

mineral

Howlite

Mohs 3.5

How to tell apart: Luster reads vitreous on Ruitenbergite and subvitreous, glimmering on Howlite.

Often found alongside ruitenbergite

Minerals reported to co-occur with ruitenbergite. 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)₉·4H₂O
Mohs hardness: 3-4
Density: 2.21 g/cm³
Colors: Colorless Light yellow
Streak: White
Luster: Vitreous
Transparency: Transparent to translucent
Crystal system: Monoclinic
Crystal habit: Bladed to tabular crystals
Cleavage: On {100}, good
Rarity: Rare
Uses: Collector
Host rock: Very rare, in an evaporite deposit

Where rockhounds find ruitenbergite

Classic worldwide localities

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

Field-hunting tip

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

Common questions

How do you identify ruitenbergite?+

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

Where is ruitenbergite found?+

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

What rocks look like ruitenbergite?+

Ruitenbergite is most often confused with Howlite, Colemanite, Halite. A quick hardness test and a streak check separate the look-alikes faster than color alone.

What minerals are found with ruitenbergite?+

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

What kind of rock does ruitenbergite form in?+

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

What is ruitenbergite used for?+

Ruitenbergite is used in collector.

Find ruitenbergite on the map

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