Åkermanite is a member of the melilite group, typically found in high-temperature, low-pressure contact metamorphic zones or within alkaline igneous rocks. It is most often identified by its tabular tetragonal habit and its occurrence alongside other skarn minerals like diopside and wollastonite.
Is this åkermanite?
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 åkermanite with a known reference. Åkermanite sits at Mohs 5-6, 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 resinous.
- 4Match the color rangeCompare against the expected color range: colorless, grayish, green, brown.
- 5Look at form & habitCrystal system: tetragonal. Typical habit: tabular crystals, massive, granular.
Often confused with
Åkermanite vs. its common look-alikes, and how to tell them apart in the field.
Often found alongside åkermanite
Minerals reported to co-occur with åkermanite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Ca₂MgSi₂O₇
- Mohs hardness
- 5-6
- Density
- 2.944 g/cm³
- Streak
- White
- Luster
- Vitreous to resinous
- Transparency
- Transparent to translucent
- Crystal system
- Tetragonal
- Crystal habit
- Tabular crystals, massive, granular
- Cleavage
- Distinct on {001}, poor on {110}
- Rarity
- Uncommon
- Uses
- Collector, Scientific research
- Host rock
- A product of contact metamorphism of siliceous limestones and dolostones, and in rocks of the sanidinite facies
Where rockhounds find åkermanite
Classic worldwide localities
- Crestmore, Riverside Co., California, USA
- Cascade Mountain, Adirondack Mountains, Essex Co., New York, USA
- Tres Hermanas district, Luna Co., New Mexico, USA
- Monte Somma and Vesuvius, Campania, and Monte Cavalluchio, Sacrofano, near Rome, Lazio, Italy
- Dufresne Hill, Oka, Quebec, Canada
- Kilchoan, Ardnamurchan, Argyllshire, Scotland
Field-hunting tip
Where it forms: A product of contact metamorphism of siliceous limestones and dolostones, and in rocks of the sanidinite facies. If you start seeing monticellite, wollastonite, spurrite in float, you are in the right ground. Typical habit: tabular crystals, massive, granular. Train your eye for that shape before scanning the outcrop.
Common questions
How do you identify åkermanite?+
Where is åkermanite found?+
What rocks look like åkermanite?+
What minerals are found with åkermanite?+
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What is åkermanite used for?+
Find åkermanite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
