Norsethite is a rare barium magnesium carbonate that often forms distinct rhombohedral crystals similar to dolomite. It is most famously associated with the Green River Formation, where it occurs in oil shales. Collectors should look for its glassy luster and characteristic perfect rhombohedral cleavage to distinguish it from more common carbonate species.
Is this norsethite?
5-step field checkRun through these checks against the specimen in your hand. The more boxes tick, the more confident the ID.
- 1Test the hardnessTry to scratch norsethite with a known reference. Norsethite sits at Mohs 3.5, softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Streak: white.
- 3Read the lusterHold the specimen under a strong light. Luster: vitreous.
- 4Match the color rangeCompare against the expected color range: white, colorless.
- 5Look at form & habitCrystal system: trigonal. Typical habit: rhombohedral crystals, massive, granular.
Often confused with
Norsethite vs. its common look-alikes, and how to tell them apart in the field.
Often found alongside norsethite
Minerals reported to co-occur with norsethite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- BaMg(CO₃)₂
- Mohs hardness
- 3.5
- Density
- 3.837 g/cm³
- Streak
- White
- Luster
- Vitreous
- Transparency
- Transparent
- Crystal system
- Trigonal
- Crystal habit
- Rhombohedral crystals, massive, granular
- Cleavage
- Good on {1011}
- Rarity
- Rare
- Uses
- Collector
- Host rock
- A rare authigenic mineral in and underlying the Green River Formation; a primary mineral in carbonatites; uncommon in metamorphosed hydrothermal mineral deposits
Where rockhounds find norsethite
Classic worldwide localities
- Westvaco trona mine, about 30 km west of Green River, Sweetwater Co., Wyoming, USA
- Iron Hill, Gunnison Co., Colorado, USA
- Rough claims, north of Sifton Pass, British Columbia, Canada
- Chipman Lake carbonatite, 350 km northeast of Thunder Bay, Ontario, Canada
- Jason Pb–Zn deposits, Macmillan Pass, Yukon Territory, Canada
- Tapira carbonatite, Minas Gerais, Brazil
Field-hunting tip
Where it forms: A rare authigenic mineral in and underlying the Green River Formation; a primary mineral in carbonatites; uncommon in metamorphosed hydrothermal mineral deposits. If you start seeing shortite, labuntsovite, searlesite in float, you are in the right ground. Typical habit: rhombohedral crystals, massive, granular. Train your eye for that shape before scanning the outcrop.
Common questions
How do you identify norsethite?+
Where is norsethite found?+
Is norsethite safe to handle?+
What rocks look like norsethite?+
What minerals are found with norsethite?+
What kind of rock does norsethite form in?+
What is norsethite used for?+
Find norsethite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
