Meridianiite is a rare magnesium sulfate hydrate that was first identified on Mars by the Opportunity rover before being confirmed on Earth. It typically forms in very cold, hydrated environments and is chemically unstable at room temperature, often dehydrating into epsomite or hexahydrite.
Is this meridianiite?
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 meridianiite with a known reference. Meridianiite sits at Mohs 2 — softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Meridianiite leaves a white streak.
- 3Read the lusterHold the specimen under a strong light. Meridianiite typically shows a vitreous luster.
- 4Match the color rangeCompare against the expected color range: colorless, white.
- 5Look at form & habitCrystal system: monoclinic. Typical habit: prismatic crystals, granular aggregates, crusts.
Often confused with
Meridianiite vs. its common look-alikes — and how to tell them apart in the field.
Often found alongside meridianiite
Minerals reported to co-occur with meridianiite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- MgSO₄·11H₂O
- Mohs hardness
- 2
- Density
- 1.47 g/cm³
- Streak
- White
- Luster
- Vitreous
- Transparency
- Transparent
- Crystal system
- Monoclinic
- Crystal habit
- Prismatic Crystals, Granular Aggregates, Crusts
- Cleavage
- Good
- Rarity
- Rare
- Uses
- Collector, Scientific
- Host rock
- Sedimentary Environments, Cold-climate Soils, Ice Deposits
- Typical price
- n/a (extremely rare specimen, mostly academic significance)
Where rockhounds find meridianiite
Classic worldwide localities
- Mars (Meridiani Planum)
- Canada (Quebec)
- Antarctica
- China
Field-hunting tip
Look in sedimentary environments, cold-climate soils, ice deposits country — that is the host setting where meridianiite typically forms. If you start seeing epsomite, hexahydrite, ice in float, you are in the right ground. Field specimens usually show a prismatic crystals, granular aggregates, crusts habit, so train your eye for that shape before scanning the outcrop.
Common questions
How do you identify meridianiite?+
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How much is meridianiite worth?+
What rocks look like meridianiite?+
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Find meridianiite on the map
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