Magnesiocoulsonite is a rare member of the spinel group characterized by its magnesium-vanadium composition. It typically occurs as small, dark, metallic octahedral grains found within metamorphic or ultramafic geological environments.
Is this magnesiocoulsonite?
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 magnesiocoulsonite with a known reference. Magnesiocoulsonite sits at Mohs 6.5, softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Streak: black.
- 3Read the lusterHold the specimen under a strong light. Luster: metallic.
- 4Match the color rangeCompare against the expected color range: black.
- 5Look at form & habitCrystal system: cubic. Typical habit: disseminated.
Often confused with
Magnesiocoulsonite vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Magnesiocoulsonite is noticeably harder (Mohs 6.5 vs. 4.5-5); streak differs, so Magnesiocoulsonite leaves black, Coulsonite leaves dark brown to black.
How to tell apart: Magnesiocoulsonite is noticeably harder (Mohs 6.5 vs. 5.5); streak differs, so Magnesiocoulsonite leaves black, Chromite leaves brown.
Often found alongside magnesiocoulsonite
Minerals reported to co-occur with magnesiocoulsonite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- MgV₂O₄
- Mohs hardness
- 6.5
- Density
- 4.3 g/cm³
- Colors
- Streak
- Black
- Luster
- Metallic
- Transparency
- Opaque
- Crystal system
- Cubic
- Crystal habit
- Disseminated
- Cleavage
- None
- Rarity
- Rare
- Uses
- Collector
- Host rock
- An accessory mineral in Cr–V-bearing metamorphic rocks
Where rockhounds find magnesiocoulsonite
Classic worldwide localities
- Pereval marble quarry, near Slyudyanka, Sayan Mountains, near Lake Baikal, Siberia, Russia
Field-hunting tip
Where it forms: An accessory mineral in Cr–V-bearing metamorphic rocks. If you start seeing cr–v-tremolite, cr–v-diopside, goldmanite in float, you are in the right ground. Typical habit: disseminated. Train your eye for that shape before scanning the outcrop.
Common questions
How do you identify magnesiocoulsonite?+
Where is magnesiocoulsonite found?+
Is magnesiocoulsonite safe to handle?+
What rocks look like magnesiocoulsonite?+
What minerals are found with magnesiocoulsonite?+
What kind of rock does magnesiocoulsonite form in?+
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Find magnesiocoulsonite on the map
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