Reedmergnerite is a rare boron-bearing member of the feldspar group, structurally similar to albite but with boron substituting for aluminum. It is most famous for its occurrences as small, transparent crystals within the oil shales of the Green River Formation in Utah. Collectors typically look for it in micro-mounts or small specimens from alkaline environments.

Hardness

6-7

Mohs

Luster

Vitreous

Streak

White

Transparency

Transparent

mineralrareFeldspar Group family

Reedmergnerite

Hardness: 6-7
Luster: Vitreous
Streak: White
Transparency: Transparent

Is this reedmergnerite?

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 reedmergnerite with a known reference. Reedmergnerite sits at Mohs 6-7, 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, beige yellow, orange.
5
Look at form & habit
Crystal system: triclinic. Typical habit: prismatic crystals, blocky.

Often confused with

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

Often found alongside reedmergnerite

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

All properties

Chemical formula: NaBSi₃O₈
Mohs hardness: 6-7
Density: 2.70-2.78 g/cm³
Colors: ColorlessBeige yellowOrange
Streak: White
Luster: Vitreous
Transparency: Transparent
Crystal system: Triclinic
Crystal habit: Prismatic crystals, blocky
Cleavage: Perfect on {001}
Rarity: Rare
Uses: Collector
Host rock: As authigenic crystals along bedding laminations, in brown dolomitic rock and black oil shale from well cuttings (Duchesne Co., Utah, USA)

Where rockhounds find reedmergnerite

Classic worldwide localities

Joseph Smith #1 well, near Duchesne, Duchesne Co., Utah, USA
Wind Mountain, Otero Co., New Mexico, USA
Dara-i-Pioz massif, Alai Range, Tien Shan, Tajikistan
Lovozero massif, Kola Peninsula, Russia

Field-hunting tip

Where it forms: As authigenic crystals along bedding laminations, in brown dolomitic rock and black oil shale from well cuttings (Duchesne Co., Utah, USA). If you start seeing eitelite, shortite, nahcolite in float, you are in the right ground. Typical habit: prismatic crystals, blocky. Train your eye for that shape before scanning the outcrop.

Common questions

How do you identify reedmergnerite?+

Mohs hardness is 6-7. Luster: vitreous. The streak is white. Common colors include colorless, beige yellow, orange.

Where is reedmergnerite found?+

Notable localities include Joseph Smith #1 well, near Duchesne, Duchesne Co., Utah, USA; Wind Mountain, Otero Co., New Mexico, USA; Dara-i-Pioz massif, Alai Range, Tien Shan, Tajikistan; Lovozero massif, Kola Peninsula, Russia.

What rocks look like reedmergnerite?+

Reedmergnerite is most often confused with Albite, Orthoclase. A quick hardness test and a streak check separate the look-alikes faster than color alone.

What minerals are found with reedmergnerite?+

Reedmergnerite commonly co-occurs with Eitelite, Shortite, Nahcolite, Searlesite, Leucosphenite, Aegirine. Spotting any of these in float or country rock is a useful trip signal.

What kind of rock does reedmergnerite form in?+

Where it forms: As authigenic crystals along bedding laminations, in brown dolomitic rock and black oil shale from well cuttings (Duchesne Co., Utah, USA). Working float back to the host body is the standard way to chase a fresh occurrence.

What is reedmergnerite used for?+

Reedmergnerite is used in collector.

Find reedmergnerite on the map

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