Eitelite is a rare sodium-magnesium carbonate primarily associated with evaporitic environments like the Green River Formation. It typically occurs as small tabular crystals or in massive form, often found embedded within oil shales or associated with other rare carbonate minerals.

Hardness

3.5

Mohs

Luster

Vitreous

Streak

White

Transparency

Transparent

mineralrare

Eitelite

Hardness: 3.5
Luster: Vitreous
Streak: White
Transparency: Transparent

Is this eitelite?

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 eitelite with a known reference. Eitelite sits at Mohs 3.5, 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: tabular crystals, massive, granular.

Often confused with

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

How to tell apart: Eitelite is noticeably harder (Mohs 3.5 vs. 2.5).

Compare →

Often found alongside eitelite

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

All properties

Chemical formula: Na₂Mg(CO₃)₂
Mohs hardness: 3.5
Density: 2.737 g/cm³
Colors: Colorless White
Streak: White
Luster: Vitreous
Transparency: Transparent
Crystal system: Trigonal
Crystal habit: Tabular crystals, massive, granular
Cleavage: On {0001}, excellent; and another transverse to {0001}, conspicuous
Rarity: Rare
Uses: Collector, Scientific study
Host rock: An authigenic mineral in dolomitic shale and bituminous marlstone (Utah, USA); from an alkaline igneous pluton (Khibiny massif, Russia)

Where rockhounds find eitelite

Classic worldwide localities

Drill core in the Kermit Poulson No. 1 well, Green River Formation, in Duchesne Co., Wyoming, USA (type locality)

Field-hunting tip

Where it forms: An authigenic mineral in dolomitic shale and bituminous marlstone (Utah, USA); from an alkaline igneous pluton (Khibiny massif, Russia). If you start seeing reedmergnerite, leucosphenite, searlesite in float, you are in the right ground. Typical habit: tabular crystals, massive, granular. Train your eye for that shape before scanning the outcrop.

Common questions

How do you identify eitelite?+

Mohs hardness is 3.5. Luster: vitreous. The streak is white. Common colors include colorless, white.

Where is eitelite found?+

Notable localities include Drill core in the Kermit Poulson No. 1 well, Green River Formation, in Duchesne Co., Wyoming, USA (type locality).

What rocks look like eitelite?+

Eitelite is most often confused with Dolomite, Magnesite, Nahcolite. A quick hardness test and a streak check separate the look-alikes faster than color alone.

What minerals are found with eitelite?+

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

What kind of rock does eitelite form in?+

Where it forms: An authigenic mineral in dolomitic shale and bituminous marlstone (Utah, USA); from an alkaline igneous pluton (Khibiny massif, Russia). Working float back to the host body is the standard way to chase a fresh occurrence.

What is eitelite used for?+

Eitelite is used in collector, scientific study.

Find eitelite on the map

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