Magnesite is a magnesium carbonate mineral that typically forms massive, porcelain-like white nodules rather than well-developed crystals. It is frequently associated with serpentine rocks and is often used as a substitute for more expensive white stones in lapidary work.
Is this magnesite?
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 magnesite with a known reference. Magnesite sits at Mohs 3.5-4.5, softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Magnesite leaves a white streak.
- 3Read the lusterHold the specimen under a strong light. Magnesite typically shows a vitreous luster.
- 4Match the color rangeCompare against the expected color range: white, gray, yellow, brown, colorless.
- 5Look at form & habitCrystal system: trigonal. Typical habit: massive, granular, cryptocrystalline, rarely rhombohedral crystals.
Often confused with
Magnesite vs. its common look-alikes, and how to tell them apart in the field.
Often found alongside magnesite
Minerals reported to co-occur with magnesite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- MgCO₃
- Mohs hardness
- 3.5-4.5
- Density
- 3.0 g/cm³
- Streak
- White
- Luster
- Vitreous
- Transparency
- Translucent
- Crystal system
- Trigonal
- Crystal habit
- Massive, Granular, Cryptocrystalline, Rarely Rhombohedral Crystals
- Cleavage
- Perfect Rhombohedral
- Fluorescence
- Often White to Light Green Under SW UV
- Rarity
- Common
- Uses
- Industrial, Collector, Lapidary
- Host rock
- Ultramafic Rocks, Hydrothermal Veins, Sedimentary Evaporite Deposits
- Typical price
- $5-30 for specimens, $10-50 for lapidary material
Where rockhounds find magnesite
6 mapped spotsClassic worldwide localities
- Austria
- Brazil
- China
- Greece
- USA
- Australia
Field-hunting tip
Look in ultramafic rocks, hydrothermal veins, sedimentary evaporite deposits country, the host setting where magnesite typically forms. If you start seeing dolomite, calcite, serpentine in float, you are in the right ground. Field specimens usually show a massive, granular, cryptocrystalline, rarely rhombohedral crystals habit, so train your eye for that shape before scanning the outcrop. In the U.S., the densest reported localities are in Maryland, Pennsylvania, New Jersey. Start trip planning there.
Common questions
How do you identify magnesite?+
Where is magnesite found?+
Can I find magnesite in the United States?+
How much is magnesite worth?+
What rocks look like magnesite?+
What minerals are found with magnesite?+
What kind of rock does magnesite form in?+
What is magnesite used for?+
Find magnesite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
