Chlormagaluminite is a rare layered double hydroxide mineral typically found in carbonate-rich rocks within alkaline massifs. It most commonly appears as white to colorless tabular crystals or delicate aggregates, often forming in association with other rare secondary minerals in cavities. Collectors primarily prize it for its unique chemical structure and specific occurrence in famous Russian mineral localities.
Is this chlormagaluminite?
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 chlormagaluminite with a known reference. Chlormagaluminite sits at Mohs 1.5-2.5, 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 to pearly on cleavage surfaces.
- 4Match the color rangeCompare against the expected color range: colorless, yellow brown.
- 5Look at form & habitCrystal system: hexagonal. Typical habit: aggregates, hexagonal, pyramidal.
Often confused with
Chlormagaluminite vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Luster reads vitreous to pearly on cleavage surfaces on Chlormagaluminite and satiny to greasy or waxy on Hydrotalcite.
How to tell apart: Luster reads vitreous to pearly on cleavage surfaces on Chlormagaluminite and pearly on Meixnerite.
Often found alongside chlormagaluminite
Minerals reported to co-occur with chlormagaluminite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Mg₄Al₂(OH)₁₂Cl₂(H₂O)₂
- Mohs hardness
- 1.5-2.5
- Density
- 1.98-2.09 g/cm³
- Colors
- Streak
- White
- Luster
- Vitreous to pearly on cleavage surfaces
- Transparency
- Semitransparent
- Crystal system
- Hexagonal
- Crystal habit
- Aggregates, hexagonal, pyramidal
- Cleavage
- {0001}, perfect
- Rarity
- Rare
- Uses
- Collector
- Host rock
- In iron-ore skarns in an explosion pipe
Where rockhounds find chlormagaluminite
Classic worldwide localities
- Kapaevskaya pipe, middle Angara River, Irkutsk district,southern Siberia, Russia
Field-hunting tip
Where it forms: In iron-ore skarns in an explosion pipe. If you start seeing magnetite, magnesian chlorite in float, you are in the right ground. Typical habit: aggregates, hexagonal, pyramidal. Train your eye for that shape before scanning the outcrop.
Common questions
How do you identify chlormagaluminite?+
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What rocks look like chlormagaluminite?+
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Find chlormagaluminite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
